Level character in around 24-48 Hours
Player ONE is the one who needs to level a combat character to 90.
They can group up with someone else around their same level and do grind together.
Get some armor ready because you will be level 22 in minutes.
If you are respeccing from cl 90 trader or ent make sure before hand to equip any GCW weapons and jewelry and high statted/level packs.
Respec to for example Medic for the heals. You will be cl 5 probably. If you have a high level weapon still equipped it will unequip if you log for a while or if server resets.
Have your cl 90 trader buddies or alts each get a new snazzy cl 90 droid with as much cap/specials as possible as well as some spare batteries. Don't settle for a wussy droid!
Head to a player city out in the boon docks with a mission terminal.
Temporarily group up with your level 90 buddies and have them get some cl 90 missions all in the same direction. Have them send wps to player ONE if you want after they drive out and spawn the lairs and come back and get more. Get a bunch that you can farm so they are close together.
Don't get missions of animals that help each other like quenkers or fierce piket protectors.
Have the cl 90 friends ungroup or kick them.
Have player ONE be group leader.
Have each trader call their droid and set up a macro like:
/ui action toolbarSlot00 (droid special)
/ui action toolbarSlot01; (droid special like flame jet) etc
You can custom make your macros to have them follow Player ONE etc.
Each trader with a droid trains their pet to attack, group, follow and befriend. I suggest training each droid with a different group command in case ONE needs to group one that got auto stored.
Train them with same attack command like attack or att or a. Same for follow.
Each trader targets Player ONE and befriends each droid to ONE.
Player ONE says follow and all of them will not be under Player ONE's control.
Have the traders use their macros to auto fire the specials and either have them range healing Player ONE or just following along.
Player ONE can either group the droids or not to give them buffs etc.
Now take your mini army and milk (don't kill the lairs) the cl 90 animals for about 2500 xp a kill.
When you get tired of this, use your favorite afk spot to continue like North of Coronet where there is a group of high level npc you can grind off afk.
So don't have the cl 90 toons in the group with you when you start or the xp will get nerfed. Bring extra batteries. Make sure Player ONE doesn't have their own personal droid out.
Basically in a nut shell the cl 90 traders befriend their uber droids to Player ONE and you are a killing machine and can do this solo with alts or with your friends also leveling.
If you are smart with macros and afk'ing you might just be able to do all of this afk and even faster!
I got my character to 90 in less than 40 hours and that was with breaks and such.
* combat toons befriending their droids will work too; their droid will just be cl 60, but still effective.