You can easily lvl a new/low toon with help of just 1 friend between lvl 35-50.

U need a couple attack powers (if u have some Veteran attack powers u can do this right away lvl1) so u might have to fight to lvl 6

then get a higher lvl friend to team with u, depending on their lvl got to a zone that has bosses that r white or blue to him (u can fight greys too, easier when u first start) i play CoV so my examples will apply to that. Lackeyed to a lvl 34-45 got to Sharkhead and find some Hellfrost demons. Once u find one u, and u only beat him downto bout a 1/4 of his life. Then run far enough back to where u r out of lackey range and quit ur team (DO NOT UN-LACKEY FIRST). Once u quit, ur buddy can defeat the Hellfrost, he wont get anything out of it but u will get huge XP. If ur buddy is lvl 45-50 go to Grandville and fight bosses on the beachs surrounding the city walls.

NOTE: If ur mentor attacks before u quit team or uses an aggressive toggle on the target, ur XP will be greatly decreased. Kinectics work best as a mentor, SB+Heal+End Drain = Survivablilty for u and quicker time over all.

This may not work now with Issue 16's release because of the auto-exemp feature they put in.