Mountain bike would be a more enjoyable way to explore park and the areas around here?

 Just moved to Mesa at the edge or Usery park. Can walk into park and have been doing that but seems like a mountain bike would be a more enjoyable way to explore it and the areas around here. At 6'2" 240lbs looking for my first mountain bike. Sadly can't find anything. Any suggestions or help? Photo out of my kitchen window for reference

If you have Mountain bike there you can find Bike seat for Men Comfort