That mileage will go up so don't limit yourself right now.

Choice and type of bike is up to you but I do suggest trying all types of bike- Comfort- Hybrid ( Or fitness I think you may call them)- road- and any other type of bike that takes your fancy. My only suggestion is that unless you are in for aggressive trails or the trails are in bad repair in your area--Then stay away from suspension. Suspension in the cheaper form does not work efficiently and although it may take some of the sting out of potholes- it does detract from cycling efficiency on the paved roads and trails.

And when I say all bikes- I mean that. Do not exclude road bikes from your testing.