Assuming you are applying for SSDI, income from interest, other LTD and assets are not a consideration. However, income from working is. You are currently over the SGA limit. SGA means Substantial Gainful Activity, which is about $930 a month.
Generally lawyers will recommend that you stop working altogether when you apply for SSDI. The reason is that you will have to prove that "if you can work part time, why can't you work full time", which is a lot harder to prove than "I can't work at all, therefore I can't work full time".
I have heard of some people who have gotten approved while working part time (below SGA). I have also heard of people who work part time for cash so it won't be reported. Not to cheat the system, but to survive while they wait 2-3 years to get approved.
I recently read of somebody on one of the boards who had their student loans absolved because of disability. In other words, they don't have to pay them back.
The next question is, how reliable is your LTD? Are they going to cut you off in two years? Are they requiring you to apply for SSDI? You should look at your Plan Description and see what the terms are. Also try to get a feel for how your company has treated other PWC's.
The next question is, how confident are you that you will be able to maintain your part time schedule for years to come?
I would also get an opinion from the Disinissues Yahoo Group and talk to a couple of lawyers.
I would say, you are actually doing pretty good right now, but potentially in between a rock and a hard place in the future, depending on the LTD and your health.
In any case, you should be aggressively cutting expenses - get that student loan absolved, move to a cheaper place, cut off cable TV, quit eating out, etc.
Check out Your Money or Your Life by Joe Dominguez and Vicki Robin for detailed info on how to do this.