Do I have other options if I were able to upgrade to Premium?

Scour good cashflowing deals and be aware of any rehabs that need done (and pay a good inspector as well to document what needs repaired or upgraded). 

I found a house(2 unit) that was listed for $259k, I viewed it and got three contractors to give me the estimated cost to upgrade from the 1955 year it was built.

This is a timely post as I am quoting a K&T upgrade on a house here in NH this week. 

Lots of others using other great strategies though, renovations, undervalued markets, upgrading amenities, etc..

I prefer the desktop software as opposed to the online version, just because it allows me to have my data available anywhere my laptop might be (whether or not I have Internet access).I tend to upgrade every 3 years or so -- generally there aren't any updates so important or useful that having to update is necessary, and my accountant will support QB versions back 10 years.That said, I know a few people who use the online version and they like it...

What most people seem to forget though is that Detroit Metropolitan, Michigan has all the ingredients of a perfect long-term investment and with the "Big Three" getting back on their feet and showing quarterly earnings and with plans of demolishing tens of thousands of homes and rebuilding eco-farms, parks, and many other new and exciting things in the city, my city is the perfect investment in my eyes for any investor!

It appears that maintenance would be relatively low due to the recent upgrades, but would I be able to sell this 10-15 years down the line?

Here we go....If you are going to make this conversion (and you want to do it right) you are going to want to chheck with your city to see what upgrades you may have to do.

For example, if costs to fix up a facade were greater than anticipated, or to upgrade wiring in the property, etc.