ok Adam!
Travel to and from is pretty simple, its getting out thats a nightmare.
I stayed in a hotel in a town called Namur, purely because it was cheaper and available! Took about an hour to get to Spa at about 4am!
yes we only had gneral admission and oh how we wished we had grandstand seats, battling with crazy Jos Verstappen fans to be able to see the big screen!
Having a big screen tv is V important I think, and this is where spa facilities cant compete with say Monza. If you are concerned about how much you are going to have to spend on tickets, then def general admission, because somehow you will def be able to find a big screen.
I have a few friends who have camped at Spa and they loved it, although they were disappointed with the facilities. If you have gen admission tickets, then it rains it gets real mucky there, personally I would book hotel and a car and do the drive in... but thats down to personal taste and budget restraints. If you can afford hotel and car and dont mind travelling in each day then I would go for that.... Then you just need to decide where to stay!!