This is from an older post of mine, but I still have the same computer setup:

I run 6 instances of LoTRO on my PC:
64 bit Windows 7 Professional
i7-920
12gigs DDR3 ram
2x NVIDIA GTX 285 (not in SLI, I have each one running a monitor)
Intel SSD with one install

I have one instance running on one monitor, I left the graphic settings at the normal defaults. The other 5 are running on the second monitor, and I turned the settings down to low. I used IS to spread out the processor cores among the 6 instances, I forget the exact distribution.
Everything loads very fast off the SSD, I use the mouse broadcasting in IS to click the login button for all 6 characters at once and they all load in right away at the same time. Same thing for zoneing into instances and buildings, it only takes a couple seconds for everyone to zone.

I was around 30% CPU, and 55% RAM usage while playing.

3. For a follow macro here is what I do. On all your slaves enter the following chat commands:
/alias ;follow /follow
/shortcut 9 ;follow

Replace the number 9 with the quickslot bar # you want the shortcut to appear in.

In ISBoxer I have a mapped key set up that sends F2 and 9 to all other windows.

I have "auto skill forwarding" option enabled on all the slaves and just have them keep the main character targeted.

"F" is the default assist key, and "U" is the default interact with target key. So you can set up something to send those keys to your slaves and they will assist the main character and interact with the target.

4. Questing is a good idea because it progresses deeds which unlocks virtues and all that other stuff, so I figure you might as well do quests when you are the appropriate level. Of course you can always grind mobs and then go back and steamroll through zones to complete the quest deeds.