Depends on your background and how long you have been out of education.
The course it's self isn't actually that hard some people try and kid themselves that its degree level. Its maybe 1st year level or an access course if that. It's the sheer volume of the stuff which causes the problems.
If in the past you haven't had any problems self teaching yourself using pre prepared materials. Go for distance learning. If you have always suffered problems with self motivation when it comes to studying go for full time.
But don't worry peoples minds work in different ways and if you struggle on the engineering type stuff. You can be assured that the engineering type people are going through hell on earth with air law and ops procedures.
Personally I had 2-6 pints down my neck before i could even open those two books (god bless feedback)
Either Bristol or Oxford will do the job. As your in the US Naples also do ATPL theory i believe but i can't comment if its good or bad.
Some cheap books that will do for the basics and to reference to during your studies
http://www.amazon.co.uk/exec/obidos/...865963-4294069
http://www.amazon.co.uk/exec/obidos/...roduct-details
This maths book is a bit more expensive but the uni's seem to like it for access courses for engineering. Proberly over kill but hey better to much than to little.
http://www.amazon.co.uk/exec/obidos/...865963-4294069
MJ