Look at the comps in your market, having extra storage is a bonus so as long as it has working electrical I wouldn't spend much time or money on it other than making sure it's clean for showings.

Hi everyone, a couple of years ago I bought my house and around a year ago I decided to make some extra income and rent a room through airbnb.

The trifecta is making the owner and property manager happy, compensating for the extra risk, issues, and potential repairs, and encouraging the resident to limit the number of pets and be sure they are not damaging the property. 

@Clifford C Toth No, I don't rent them furnished, although in my market you can get an extra $50/BR for doing so.I have a 3rd party do the lawn 2x/month.

@Mary Jay, to layer on to Connor's comment, while some lenders will only pay draws on invoices paid with lien releases, there are also some that will allow you to submit draws on invoiced work.  

Now out of that small percentage, there's an even smaller percentage where the extra 1/10th of a second you get by carrying open makes a difference.

Also, it is okay to go through some extra maintenance for the short term. 

We plan to take all extra income after that and pour it into real estate investing.

I'm contemplating this decision because I'm not sure if it would be desirable for tenants to have an extra room instead just a loft area.

Just keep it in your personal name and get extra liability on your insurance.