The thing about RAF is you would have to level a toon 1-60 to get grantable levels. So 1-60 RAF or 48-80 no RAF. Since 60-80 is no RAF bonus anyway it's a simple choice, unless you just want to level up a bunch of other toons.

Just boost your 48 through UD Strat until 55 then Ramps until 60 (or keep going if you get bored). Then just solo quests, grabs some of your group for the group quests. You can start boosting him in UK at 65. I would also recommend that you do some heroics on your main team. Build up Frozen Orbs and nice gems/enchants (if you have those profs) so you can get your 5th as geared as possible when he hits 80. You'll have the cash for any BOE stuff you need if you do.