Carlisle, UK

What kind of budget do you have for your accommodation, are you looking for B and B, or a full service hotel.? Will you have a car?
What are your interests? There is just loads of sightseeing on both sides of the border so narrowing it down a bit would be helpful.
That'll make it easier to answer.
I had three places I used personally for overnight stays in the city, 2 basic, one for a splurge- none of which survived Covid. My splurge place was really sad, as they were wonderful.
But there is still loads of choice from quality hotels to B and B. plus Premier Inn, Travelodge and Ibis.

What is drawing you to Carlisle? What sort of things are you hoping to see and do? It doesn't sound like a dart over the shoulder, so what's the draw? Or is it a cruise ship stop?

Carlisle certainly isn't a cruise ship call. No ships of any kind have reached Carlisle in a very long time, since the early 1800's.
A canal was built to Port Carlisle, about 10 miles away, converted into a long closed railway. The port silted up and is long abandoned.
Newcastle, Glasgow, Liverpool and Barrow (very rare) are the closest cruise ship ports.

The most obvious placces are the Castle, Cathedral (don't miss the cracks and wonky arches around the central tower or the medieval paintings on the back of the choir stalls - pull the curtians back to see them), Tullie House Museum (one of the best museums for Roman remains).

Tullie House Gardens aren't very big but a lovely place to drop out.

The Cathedral refectory is recommended.

Brampton is a nice small town and nearby is Lanercost Priory. A bit further east and you have Hadrian's Wall.

Going north you are into the Borders with their ruined abbeys or Dumfries and Galloway...

The Tullie House museum really is fantastic. That was our big stop in Carlisle, besides a pub, during our 10-day trek along Hadrian’s Wall. Here’s their Website: https://www.tulliehouse.co.uk/ .

For what it’s worth, you could take a short taxi ride out to the gazebo that marks the recognized western end of where Hadrian’s Wall (and our trek) started, at Bowness-on-Solway. Maybe a silly photo op, maybe a significant place of interest. There’s no standing bits of Wall left there - it’s been dismantled for building materials over the last 1,900 years, but if you head east from Carlisle, there are surviving ruins of Roman forts, milecastles, and Wall fragments, plus more museums.

I'm always surprised when people talk about having walked Hadrians Wall west of Carlisle, that you rarely hear mention of Burgh by Sands. This village, at about the 2/3 point between Bowness and Carlisle has the King Edward I monument- a tall tower on the marshes where he died in 1307, also St Michael's Church should be visited. The Church is one of the best (and early) examples of a fortified church and pele tower where the population took refuge in the frequent raids of the Border Reivers.
There is very good interpretative material inside.
If walking the wall route between Bowness and Carlisle check the tide times and heights as the section between Drumburgh and Bowness floods at certain spring tides. Not very often, but it does happen.

While waiting for the OP to come back with more detail a couple more things-

When in the Cathedral talk to the friendly welcomers, or you may miss tidbits like part of the Cathedral being demolished during the English Civil War to use the stone to strengthen the Castle, or it being used briefly to imprison Jacobites (more of that below)

Another interesting and unique aspect of Carlisle is the State Management Scheme of Pubs in WW1- an interesting social experiment. You can read more about it on this website, which also has a trail you can follow. You should have a meal and drink in one of the surviving former State Pubs.
This was necessary because of the influx of ammunition workers in WW1. To find out all about that story go to the Devil's Porridge Museum at Eastriggs. One important footnote of WW1 is that the worst railway accident in British History happened to a troop train at Quintinshill, near Gretna. There are memorials to that too.
https://thestatemanagementstory.org/

Back to the Jacobites. This was absolutely not just a Scottish thing.
North Cumbria had it's share of Jacobite incidents. If you go to Brampton, in a quiet glade on the edge of town you should see the Capon Tree monument- where six Jacobite prisoners were hung, drawn and quartered.
And if you take the time to travel on the old A6 (not dashing down the parallel M6) there is the little village of Clifton a couple of miles south of Penrith, 20 miles from Carlisle. Here there was the battle (or skirmish- accounts differ) of Clifton Moor. There are memorials and interpretation there both to the Scottish and English armies. Another little known memorial to that skirmish is the chandeliers in St Andrew's Church, Penrith.
On the way from Penrith to Clifton you pass through Eamont Bridge where there is a prehistoric henge called Arthur's Round Table.

One of the up posts said- why go to Carlisle.

Here I have merely touched on the multiple layers of 2000 years of history in Carlisle and area, far beyond the Romans. That is why you should go.

This is all before the obvious, the well known places.

If your visit co-incides with one of these guided walking tours of the city you should absolutely take it.
https://www.greatguidedtours.co.uk/tours/carlisle-secret-city-walking-tour/

We stayed at the north Premier Inn listed as M6 Jct44 in Carlisle last June. We thought it was a nice hotel with a good restaurant attached. There was also a grocery store nearby if you want to stock up on road trip snacks. I will share that it did have a bit of an odd configuration. From the lobby, you had to go down stairs which took you to the lower floor and then back up to get to the main floor again. And the entire hotel is off one very long corridor. We had opted for the Premier Plus room in this location and it ended up those rooms were at the end of what felt like a 1/2 mile long walk to get to the far end of the building. If you have ever been on an ocean cruise ship and looked down a long hallway corridor from about midship, it looked like that.
We stayed just one night and we chose this location for convenience on our drive from Scotland heading back south into England so we knew it was a quick stop and we just wanted the basics.

That PI wasn't built as a PI. It was another of the more upmarket hotels which closed and was then taken over by PI- I can't remember it's old name off hand. That's probably why it's a bit of an atypical layout.

Is the OP still wanting assistance as they haven't acknowledged any of the preceding posts? (to this or their Cardiff post), and have not provided any additional information which might allow pertinent practical assistance to be given.
There would be no point in spending time listing every accommodation in the city, if they are looking for something only budget, or something only very high end. Nor is it practical to list every possible tourist attraction.

The purpose of the trip has now been added and the fact of travelling by train, which makes what I was going to add here rather redundant, as I was going to suggest somewhere not easily accessible by train, which is a shame.

If the handfasting is in Gretna Green it might actually be more practical to stay in Gretna or Gretna Green (two different places) as Gretna does have a station.

Thanks for all the feedback. We're staying in Carlisle rather than Gretna because it seems like there's more to do there. We usually stay in mid-range hotels.

Barbera1029-
Thanks for clarifying that.
In that case I would suggest the Crown and Mitre Hotel in Carlisle. It is right in the centre of the city, so a walk of a few minutes to anywhere including the railway (and bus stations).
An imposing great old hotel, very well modernised while still oozing history, yet you can get rooms from around £100 for 2 people. May be the top end of mid range, but I think absolutely it. You're there for a celebration after all.
As well as in the hotel itself there are a number of restaurants in close distance.
But I would suggest one interesting trip out- to a village called Wetheral less than 10 minutes by hourly train.
This is a large village centred around a Village Green. The village tag line is '1300 years of history in 1300 yards.
In that 1300 yards you go from a well thought to date from St Cuthbert's time around 675AD (rebuilt in the 1200's) to a Church whose origins may date back to as early as 475AD (the present church again dates back in part to around 1200), then on to the gatehouse to the medieval priory (free entry, learn about the right of sanctuary, and a spiral staircase to the top if you choose) and on to monastic cells carved into sandstone cliffs high above the river. Opposite are monastic salmon coops, thought to be the oldest fish traps in the UK. I actually redid this walk myself 2 days ago, for the first time in years.
While there don't miss the walk from the station platform across the railway bridge which spans a dramatic river gorge. That leads across to the neighbouring village of Great Corby (for the castle, no entry, and a lovely country pub with a brewhouse next door.
Back in Wetheral there is a little tea room and village store (The 'posting pot') and across the green is the Fantails Restaurant, one of the best in the area. Less than 5 minutes walk from the station.
Three miles away, in Cumwhitton, in 2004 the only Viking burial cemetery in England was found. Some of the rich grave goods found in the graves should by now be at Tullie House. Not worth walking up to Cumwhitton.
If you are very lucky, like I was on Tuesday, you will find the person with the key to the Howard Mausoleum (the Howards of Corby Castle) in the Church. That Mausoleum has a breathtakingly beautiful and moving 18th century sculpture in remembrance of a mum aged 23 who lost her baby in childbirth, the baby also died. It is a sculpture of national importance, but almost unknown outside the local area. When Wordsworth saw it he wrote an ode of appreciation, displayed alongside.
I went into the Church by chance, it was not on my business agenda for the day, with zero expectation of seeing the sculpture and just bumped into the keyholder who was so helpful.
This is a walk and visit you won't find in the guidebooks. But it's so worthwhile.
If I could attach images I would.

By the way I just loved that a quick in and out business trip on Tuesday by accident became a tourist trip in my own county to a half forgotten place like Wetheral. I was actually going to Cumwhitton (not for the Vikings)- where I've said there's no need for you to go to. Cumwhitton is just a tiny hamlet with a stream running down the side of the one and only street, a Church and a pub.
I'd been tasked to visit that country Church.

Thank you for that post about Wetheral isn31c. It brough back happy memories of a walk we did there many, many years ago. Wetherall is lovely and we took the footpath south along the banks of the River Eden. It was a lovely out and back walk through meadows with cows. However, the previous night there had been heavy rain over the fells. On the return walk, the river level had risen and was covering the footpath in places and we were having to jump from tussock to tussock to keep feet dry. Happy memories!