Great advice above about selling it in the park - put a for sale sign on it, then post it on the bulletin board in a community area.
Look up it's value here:
NADA GuidesIf all else fails, put it in Craigslist - lots of people looking for used units there - but since it has sat for a while, the tires at least will need to be replaced - and who knows what else needs to be done prior to towing it. Best bet is to try to sell it to someone who isn't going to move it.
You didn't say if she owned the lot it is on - most likely rents it. Talk to the management. Maybe they can help out - you never know.
Good luck
