Sounds like you already have a great product. Rather than thinking about the next technical project, focus on revenue and income and let that drive your technical direction.

Seems like your product might be in a good position to get some local advertising revenue. There are probably lots of smaller independent businesses that cater to hikers and would love to boost their traffic. Spend some time talking with them.

UPDATE: Perhaps collect some information regarding the most frequently accessed locations on your maps and target businesses in that area.