Topographically speaking, I live in a bowl. There is probably a good 50-100 foot elevation difference from where I live to the highway outside my neighborhood. So, a huge mast is not really an option. What’s my best antenna option for my handheld or a base station for VHF/UHF? Or, do I need to buckle down on my general license and focus on HF?
Well, who is it you want to talk to? VHF/UHF or HF are two very different parts of amateur radio. VHF/UHF is good for local communications. HF is more longer distance stuff.
With a hand held, it's very unlikely any amount of hand held antenna is going to get you out of a 100 foot deep hole. Your best hope is that there is a repeater nearby that you can reach. VHF/UHF is mainly line of sight, so if you can't "see" any repeaters from your hole, there's not a lot you can do other than a 100 foot + tall tower.
For HF, being in a hole isn't going to help, but isn't as much of a hindrance as VHF and UHF. any decent antenna will work, but you might want to look at NVIS type antennas that will throw your signal mostly straight up and bounce off the ionosphere and back down.