Wow. Here, of all places, no one suggested a KLR250. Or a SuperSherpa if you *need* electric start. *pppssshhh*
Wow.
Good bike, indestructable, street legal so you can practice, light and easy to ride in dirt. Great gas mileage, cheap to insure.
Get some good dirt experience under your belt, have a good time doing it. Then ride your bike to and from where you are going, build from there. Heck, get your dad riding off road a little bit, plant that seed, you'd be surprised how far that can go.
And, FYI, any thread you start with the "I want to ride but my 'rents won't let me." is going to generate another thread about that, and not the bikes....