For me, it comes down to scheduling. When I'm good about keeping to a schedule, I can handle all the writing, RP, and other things I like to do/need to do. I also have been trying to take note of the times my RP partners are online. I've got a couple hours' "downtime" for example, during the day when the "morning crew" aren't on and the "evening crew" aren't on, so I tend to read, write, do chores, etc during that window.
Of course, this only works when I'm home for the summers. During the school/work year, I try to set aside the time right when I get home as "me time" - so I write or read or whatnot then (nothing on the computer), and wait till dinner to come online and RP and check email and stuff.
Striking the balance is hard for me, too. It's why I'm still on the same page a week and a half later, despite the binder being *right here* next to my computer.