Berkshire, Bath, Sheffield, Belfast, Newcastle, Lancaster, Glasgow, Portsmouth

Do you have to visit these places in this particular order? It is a long way from the most convenient route. The more logical route for me would be Berkshire, Portsmouth, Bath, Lancaster, Glasgow, Belfast, Newcastle and Sheffield, assuming you have to get back to London.

Why are you planning to go from Sheffield to Belfast via Leeds, especially if you don't want to visit Leeds? It would make more sense to get to and from Belfast via Newcastle and Glasgow where there are direct flights.

It's clearly a typo but where is Fort Colins? The only one I can find is in Colorado.

You could go from Leeds to Chester on the hourly through train. Use Chester as a base for North Wales, then the hourly Chester to Liverpool South Parkway direct train for Liverpool Airport (flights to Belfast) flying back from Belfast to Newcastle airport.

Edinburgh is 90 minutes by train from Newcastle and York about 75 minutes by train from Newcastle, so those are easy day trips. Choose your trains right and Newcastle to Edinburgh can be as low as £10 day return and York £15 day return (with a railcard 1/3 off reductions).

Ambleside is an easy 2 hour ride on the hourly bus from Lancaster (half hourly from 1 July to 27 September-the extra bus is over 30 minutes faster as it is a motorway express between Lancaster and Kendal). 1st bus out at 7am, last back just before 7pm. You can even buy a bus and boat combined bus ticket which includes a trip on the Windermere 'steamers' [much less than the sum of the two parts].

Newcastle to Lancaster is just over 2 hours on the train- get Advance Fares NCL- Carlisle and Carlisle to Lancaster, and with a railcard that can be as low as £2 + £5.

From Newcastle Hadrian's Wall, Northumberland and the much neglected Durham Coast are obvious day trips.
Go North East (for the wall and the Durham Coast) and Arriva (for Northumberland) have very good value day tickets.

You can save time going from NCL to Northumberland by using Advance Train fares to Morpeth, Alnmouth or Berwick.

On your way from Newcastle to Lancaster rather than taking the direct train from Carlisle to Lancaster in 50 minutes you can come round the Cumbria Coast in 4 hours. The Coast line is one of the UK's unheralded great scenic lines, especially south of Maryport.
The service is hourly (half hourly in mid afternoon).
Anyone over 55 can buy an Explorer 55 day rover ticket for £18.40 to hop on and off at will. Or just stay on for the full ride- on some trains change at Barrow in Furness.

(Yes, hands up it is my local line but that does not detract from it's scenic splendour).

That £18.40 ticket extends all the way to Liverpool, Manchester and Chester on Northern Rail trains only (so could be used from Lancaster to Chester via Manchester in a bit over 2 hours each way for instance). Valid after 0930 Mondays to Fridays, any time at the weekend. No railcard needed, just proof of age.

There are flights from Glasgow to Southampton- for Portsmouth.

PS- If you go to Ambleside on a Saturday before the end of August you could stay on for the Evening Buffet Cruise with live music on Lake Windermere from 1900-2130 then the last train back from Windermere to Lancaster at about 2230. That cruise has to be pre-booked as it is very popular locally. https://www.windermere-lakecruises.co.uk/cruises-fares/buffet-cruise

Hadrians Wall is a great day trip from Newcastle. Worth more time than that if you have it.
Portsmouth , Historic Dockyard, Isle of Wight
Belfast, Titanic experience

Course Leeds can't hold a Torch to Sheffield.
Marc is on tour early September
Unless you have already " been there,done that" its impossible not to recommend a trip to York.
I am fond of the National Mining Museum too up near Wakefield

Bodnant Garden is a National Trust property in North Wales. It's lovely and is accessible by public transportation, though not terribly efficiently.

When I visited fhe area in 2017, there was a handy and money-saving public-transportation ticket covering the area of Chester and North Wales.

Rick has some coverage of the area in his guide to Great Britain.

This is a very recent thread on public transport in North Wales-https://community.ricksteves.com/travel-forum/wales/explore-wales-4-in-8-pass-and1bws-overlap

This is the North Wales One Day Rover-https://railrover.org/pages/north-wales-rover.html although it is totally not worth it just for a day visit to Bodnant and the inevitable Conwy Castle from Chester. Not that either is remotely a "hidden gem".

Bodnant is reached by Bus 25 from Llandudno Junction Station- https://bustimes.org/services/25-eglwysbach-llandudno

Hi everyone--

Thank you, I appreciate the suggestions so far.

A couple of things to address the questions

• I wasn't able to start the trip at Portsmouth as I didn't manage to secure my desired accomodation rate for earlier dates and the fact that I would need to be in London.

• Leeds because of the direct flight to Belfast.

• Fort Collins was a typo-- sorry. Don't know why I wrote that when Fort William was what I'd meant

• Would welcome any suggestions of day boat trips that are doable from any one of the spots I've made my base

There are direct flights to Belfast from many airports. Manchester would for me be easier to get to from Sheffield than Leeds.

At Belfast there is this boat tour- https://ladyofthelagan.com/

Ambleside/Lancaster we have already covered at Windermere, but at Lancaster there are also cruises on the Lancaster Canal with Kingfisher Cruises

From Glasgow there are various possible ferry trips on the Firth of Clyde- the easiest is train to the glorious Wemyss Bay station, then ferry to Rothesay on the Isle of Bute.

From Sheffield there is the Leeds water Taxi

At Bath there are river cruises and also the Bristol Harbour water bus

If you do get to Chester there are River Cruises

There are also direct flights to Belfast from East Midlands Airport