Itinerary for England and Ireland trip

Lisa - With only 10-12 days tops, I would suggest you focus on England or Ireland not both. Look at 2-3 days in Bath, 2-3 days in the Cotswold and 4-5 days in London. It's been a long time since I was in Ireland but you might do 2-3 days in Galway, 3-4 day in Dingle and 3-4 days in Dublin.

If your heart is set on doing both, you might consider something like this: Dublin, 2 days, Kenmare, 4 days (you can get to Cork, the Beara Peninsula, the Ring of Kerry, and even Dingle if you don't mind a REALLY long day from Kenmare). Fly from Cork to London. For England, stay in Londonyou can do your other England wishes as day trips from London. Several castles are doable from London.

I was in Dublin in 09 and would suggest skipping the Guiness if you don't have the time. I was disappointed and it was not cheap. Its a museum, and doesn't show you the factory. I'd go for the Whiskey tour, or the Mummy at St. Michan Church. That was ahoot! Samantha Brown had it on her program. Find the statue of Oscar Wilde, and have lunch at the roof top of Marks & Spencer. From Dublin, we flew to Cork on Ryanair and did a one day turnaround (flew out at 8 am, came home at 7 pm). Flying was dirt cheap (cheaper and faster than bus or train!) It was very easy to do in one day, and the Blarney Castle can be accessed via the express bus. The people in Cork can help you find the bus. We got the hop on/hop off multi day pass at the Dublin airport, and it included the express bus to downtown. The route the bus took was exactly what we wanted, and it ran very frequently. FYI: St Pat's cathedral is not catholic but beautiful nonetheless.

If you only have 12 nights and want to visit both England and Ireland you might want to think about spending your time in England in London (with one or two day trips) rather than spending a lot of time traveling. The Cotswolds are beautiful, but if you are history buffs and want to hit the main attractions, I wouldn't put them high on the list. Spend 1/2 day at the tower of London; 1/2 day at Westminster Abbey or St. Pauls; visit the Churchill War Rooms; take the train to Hampton Court and spend a day with Henry VIII; take the Globe Theatre tour; visit the British Museum. We spent a week in London in July and didn't even scratch the surface. In Dublin you can get to both the Guiness Brewery and St Patricks via the hop on/hop off tour. If you are interested in history, the Killmainham Gaol is worth a visit. You won't need more than 2 days to see most of the sights in Dublin; you'll need a car (or a day tour) to go beyond.

If you are visiting Dublin and interested in History I would suggest a visit to Number 29, a Georgian House museum, the whole house has been furnished with original artefacts as they would have been in the period 1790 to 1820 when it was occupied by the Beatty family, well worth a visit. One to two kilometres from the city centre and Trinity College, at the corner of Merrion Square

I agree with Ruth. We have spent a week in London the last 2 times we were in the UK and could have spent more time. I wouldn't bother with a car in London. It is really easy to take day trips by train to Hampton Court or Windsor. You might be disappointed in Stonehenge unless you must check it off your World Heritage list. You can only view it from it seemed like 50 feet away (unless you can certify you are a Druid). Bath is good for a day if you need your Jane Austin fix. Oxford is a quick trip by train and but finding a parking is a problem. But if you do want a road trip I would look up the Treasure Houses and use them as end destinations.
Blenhiem is in Woodstock not that far from Oxford. You really need 3 weeks to do UK.