Originally Posted by
BlazingPedals
You won't get much help from this corner. Road bikes don't do trails well, and mountain bikes can't keep up with road bikes on the road. You could get a hybrid that doesn't do either particularly well, or some variety that leans one way but gives up some capabilities of the other. Given your budget, you're probably looking at either used, or a low-end model at a bike shop.
Yes road bikes don't do trails well, and while mountain bikes are not as fast on the road, it depends on who is riding the bikes whether of not one can keep up. My wife rides a 29in road bike and I ride a 27.5in mountain bike and can keep up with her on the road fine as she does not ride that fast.