Upvote:2
the wheel is on the left
Not a problem.
Stay alert when starting a journey on small roads with few or no other cars around you. It is easy to accidentally start driving on the wrong side if there are no other cars in sight.
You'll have more trouble overtaking but you are unlikely to do much overtaking in a campervan and the passenger can help keep a lookout.
I don't know how much ahead we would need to book
It depends on when you are travelling - if it coincides with summer school-holidays I would book ahead.
If it is off-season, less popular areas, and/or you don't mind the risk of driving for hours looking for somewhere to stay - or finding a B&B, then you can take more risks.
I think we have scheduled too much for 14 days
I agree, It looks like you'll spend most of your time on the motorway. Some of those places can be explored in a couple of hours, others can be enjoyed for months or years without visiting the same spot twice (e.g. Wainwrights)
I'd pick one or two main centres. Aim to include places near or between those centres. Don't spend too much time driving - you'll get bored and tired.
Tired drivers have more accidents and less fun.
This is largely a matter of personality though. Some people like to have detailed, well-researched plans made well in advance, others like to be completely spontaneous and don't mind the occasional disappointment or memorable hardship.