can the grantor sign a qiut claims deed to the grantee when theres a mortgage still being payed?

A lady I've known for a couple years has had some finacial issues and owns a mobile home that she owes $21,100.00 on, it was $1,1000.00 behind on mortgage and needed alot of work, I've already started working on it and cought the payments up and she wants to sign a Quit Claims Deed with me.For whats left owed and I'm in construction and the work I can easly do with no cost just my labor.I just want to know if there is any bad down falls for me signing a Quit Claims Deed with her, exspecially since I've already have a very small investment in it and a little time in labor but I've held off on any more work until I get more information, and the mortgage payment is about to be due and the only reason I payed the late payments is it was going to be foreclosed, but I've seen the recent payment reciepts stateing everything is paid up to date and a balance of $20,000.00 is left owed.Shes a nice lady but maybe have some debt issues and I don't know if I sign the deed if it want effect me down the road after I get the place fixed up and have dumped more money in to it.Its a perfect place for me and my family and my credits not the best and don't even know that would have effect in the deed either, its not horrible but I don't have much estabilished.I would really appreciate any feed back you could give me. THANKS BRYAN 386-715-6911