Just back from doing hour building in the States and did 75 hours over the course of a month, the breakdown of the costs is below (the average exchange rate at the time was $1.61 to the £1)
Checkout ride.........................£121.46
C172 for 75 hours dry..............£2,771.81
Fuel.....................................£1,390.09
Landing Fees.........................£25.00
Maps....................................£90.00
Hotel....................................£543.84
Transport/Share of hire car......£25.00
Spending money/Food.............£755.57
Return flight to America ..........£596.05
Other bits and pieces..............£34.00
Total............................£6,352.82
This accounts for every penny (cent) I spent whilst away so if you divided the total cost by 75 hours you get
£6,352.82/75 = £84.70 per hour
or if you look at just the cost of the plane (ie. dry rate plus fuel) that would be
£2771.81 + £1390.09 = £4160.90 divide this by 75 and you get
£4160.90/75 = £55.49 per hour wet for a C172
All in all I think it was a good deal, I got to visit 24 different US States, covered 6465nm and never landed at the same airfield twice (other than the place I picked the plane up from) and only had to pay a landing fee on three occasions.
I had the option of hiring a Robin DR400 in England for £70 per hour wet but once I had factored in the landing fee's at airfields that I wanted to visit and then accommodation for the night it would of easily brought me over the cost I had in America.
In my opinion if you find a good rate in England and are happy to only stray away an hour or so from your home airfield before returning to land (to save landing fees) than England is for you, whereas if you want something a little bit different America might be for you.
I will say that if you went on your own the accommodation cost would go up (I would say double) as I did this trip with friends and therefore the price above is my share of the cost, other than that all of other costs should/would be the same.
Either way... Happy Flying!!