Depending where the sewer and water lines run, live roots can cause issues for pipes and foundations.Healthy old-growth is often attractive.

They set the opening bid so low to attract attention.

Not suggesting this will be the outcome in every instance, but concur with others that you may want to consider holding if the other aspects / fundamentals of your market remain attractive.

Take pictures of units, design flyers and bring flyers of vacant properties to local businesses to attract more and better tenants.I'm now looking for multi family buildings with 5+ units which would grow my portfolio exponentially and further create the need for a full time Property manager. 

If buying older properties im thinking one may be able to buy way more than properties build post 2000 but wondering how desirable older properties are and if not so desirable perhaps lower income people are attracted to these?

Couple that with the convenient access to NYC and it makes for an attractive alternative for many young couples and first time home buyers.  

Cynthia Craft since you live in Detroit, look for areas you know you can afford, have potential, and can attract solid tenants.

Best option is a HELOC.You may want to look elsewhere to invest. 300K homes will not have positive cash flow and remote properties attract very low quality tenants.

I don't know your area *super* well but my impression is that there aren't major tourist destinations that will attract a huge stream of visitors.

However I do want to make the units attractive so I can get quality tenants.