York or Cotswolds - 4 days - reservations needed?
 

We're going to England in April and trying to decide where to visit besides London where we already have a house exchange lined up. We were planning on the Cotswolds when a neighbor told us not to miss York so now we're struggling with exactly where to spend our few precious days outside of London. Where do you recommend and do we need reservations in April. We have a car rental and are considering just hitting the road and seeing where it takes us.

It's a 3-4 hour journey between the two. Both can fill 4 days easily and they're not that different anyway. So just go to one and don't waste too much time deciding.

York itself is, IMHO, a bit more interesting than Oxford, though it's pretty even-Stephen (York Minster's more interesting than Christ Church, though Oxford's museums beat York's). The nearby North Yorkshire countryside is more dramatic than the Cotswolds, though that doesn't make it prettier. North Yorkshire also has fewer lambs visible in early April, since it's a good pullover chillier than the Cotswolds in the spring. Cotswolds gardens will be a bit further on.

York is over twice as far from London as Oxford, and takes at least three times as long to drive. Most touristy things are a good cheal cheaper than in the Cotswolds.

While I haven't been to York yet I have to agree with flanner Uk on the weather being milder in the Cotswolds in April.
You might need accomm if your dates are over the Easter Holiday. Good friday 6th to Easter sunday 8th could get booked up at both destinations.
I would google for pictures of both locations and see what appeals to you. Both different and both beautiful. Gardens should be looking quite pretty in Cotswolds. Yorkshire is full of Hills & Valleys which are stunning and York is another City. My vote will always be Cotswolds until I see York ;-)

PS: I rarely use hotels or B+Bs in Yorkshire and never in the Cotswolds, but York seems to get booked up solid some weeks ahead most weekends these days, and Easter weekend is likely to be chocker practically everywhere.

Our dates to explore the English countryside are April 20-23