First Idea: Second-hand store.
The short of it
a. acquire road-side land and structure
b. scout thrift stores in urban areas for deals on quality products
c. return scouted products to your location
d. mark at prices to accrue a profit
I suggest this because it could be as small as you would like. Shirts, jeans, hats, books, electronics. Or. Wooden tables, matching chairs, mirrors, dressers. Yes there are many thrift stores and no they are all not quality. If you took the time to get the quality I would think that your shop would become known as that unique second hand shop. People just wait to spend money, and if they see good deals most are conditioned to think if they did not buy it as such and such a price it would make them a fool.
Second Idea: Campground
If you have acreage, especially wooded, consider the possibility of a campground. Investment might be: wo/mens bathroom, lobby, electrical hook-ups, small camp-supply store, clearing spots to camp, paving/graveling looped road. Many campgrounds charge $25/night for a bare site and more for hookups. This idea would be especially attractive if you are near natural attractions like hiking, fishing, boating ect.
if these interest you I would be willing to explore them in detail as I have been turning them over in my mind for a time before seeing this thread
also - first post. Hi IC