Where are you editing the film? At home, or in a studio? I would hire (or find for free) a sound designer / editor willing to work in their own home...if they take the job, their own home computer suite should be able to handle the job--you of course would send them the rough cut/s for them to design off of. I assume when you say sound, you're talking about sound design, foley and ADR and such correct? Well, you should definitely be as much a part of that as you can...but you don't need to be there for all the little foley and design...
And of course you and this person will want to sit down for the final mix of dialog and music...make sure it's mixed properly.
If you're talking about incidental and soundtrack music...that's a similar deal. The musician will most likely have a home suite or office that can handle everything. You send them the rough cut, they write the music....and send you the file which hopefully you can drop into your timeline and matches properly.
Hope I helped.