A creative lease agreement for the 250k tax exclusion

[Scott Kirk]

I bought a house last summer that I'm living in while fixing up.  I plan on taking advantage of the 250k tax exclusion of living in a personal property once it sells.  I would love to rent out a spare bedroom but as I understand it, that changes the type of property to an investment property and therefore invalidates the 250k capital gains exclusion.   I think if found a creative work around that works for my situation.  I'm very busy with business and having time to cook healthy meals have been a challenge.  So I have an ad to find someone who will prepare meals in exchange for living there for free.  I talked to my CPA and he said that it wouldn't be advisable to have a lease agreement, but a living agreement of house rules he feels comfortable with.  My concern is addressing the scenario when I need someone to move out or I need to be compensated for property damage, while still maintaining the living agreement format and binding nature of a lease.  Any suggestions?  The property is in Oregon by the way.