After quite some time of not using a bike at all, I finally started again last year. I took my old bike out of storage, did some minor maintenance like new tires and tubes, and it worked well enough for one last summer - but I fear it's now breaking apart and no longer reliable.
Doing some online research about types of bikes - there are dozens, and I really don't know what exactly I need.
I will probably mostly use the bike for fitness - short trips of about an hour in the evening, or some sort of combined biking&hiking on the weekends. "Going fast" is not my primary goal. During my activities this summer, having a small backpack with me was more than enough, so I probably don't need a carrier or rack. The routes I took were mostly asphalt roads, but interspersed with some dirt tracks. The bike should be able to cope with that.
I'd like to try running some errands using the bike instead of a car, but won't be able to use it for commuting. That means stuff like splashguards or other dirt protection is probably a secondary concern.
I like the look of a Mountain Bike (except for the very huge tires of recent models), but I have no clue if another type of bike would be better suited to what I have in mind. Any suggestions for bike types, or pitfalls that I need to avoid?