The best thing to do is go try out as many bikes as you can & see what you like!!
You can probably do 20 miles or so in two hours, depending on how hard you ride.
As far as being concerned about the gears adding complication, although there is a learning curve to figure out what gear to use when, a quality bike should shift easily & smoothly with minimal problems. There won't be too much difference in this regard between a good road & good hybrid bike.
You will be more at risk for flats with a road bike on that terrain for sure. Otherwise, with a cyclocross or hybrid you can get tires like Schwalbe Marathons or Specialized armadillos to name just two.
You need to consider what your expectations are (for speed, riding up hills, your own riding ability & athleticism). I hope I’m not making an unfair assumption, but since your last bike was a cruiser, can I guess that you are probably more of a beginner cyclist?
If this is so, you would likely want something that provides you with some easier, slower gears, especially if you are going to be riding even moderate hills.
There might be two front crankset gears with 36 & 46 teeth. The smaller the gear in the front = the slower & easier it is to pedal. So 36 tooth is the low gear & 46 tooth is the high gear.
The rear cassette might have 9 or 10 gears ranging in size from 12 teeth to 30 teeth. On the rear, the larger gear is the easier / slower gear.
The front crankset will likely have three gears instead of two, like a 28, 38 & 48 tooth gear. So the gearing is significantly lower / slower / easier.
The rear cassette may have gears that go from 12 or 14 to as large as 34 or 36 teeth, again the large being a lower, slower easier gear.
(It is worth noting that the higher / faster gears on the hybrid may have the same number of teeth as the cyclocross).
The front crankset will likely have two gear, like a 39 tooth & 53 tooth gear. So the gearing on the low end is significantly higher / faster / harder.
The rear cassette may have gears that go from 12 to only 25 teeth, again the large being a lower, slower easier gear.
Also, having come from riding a cruiser, you may find the hybrid to be more comfortable.
Unless the above doesn’t apply to you (or you just really want to ride with drop bars), I’d recommend the hybrid / commuter bike.
There is one other classification of bike that you may have overlooked, Touring Bikes.
Touring bikes typically have gearing much more similar to that of a hybrid like the gearing I have noted above, but have a somewhat more aggressive riding position with drop bars (although still relaxed compared to a road bike or cyclocross).