The Best way i've found to do it is to get on the road AFTER the farplane. I preer to do boss-battle ish stuff rather than a hundred little ones, so you can run into those energy fields and fight that massive thing with wings (i forget what it called)

I went into the farplane at 38 or something on a new game plus, and by the time i got to Vegnagun i was mid 50's on P and R and 62, on yuna.

and, if you think it worth it, you can rebeat the whole game in 8 hours or so, if you newgame+ it, so you can fail the gagazet mission and get Toblis "Key to Success" item, taht doubles both EXP and AP, and you can finish gagazet for you hundred percent the second time.