You won't keep everyone happy, but stick to the band plan as close as you can and stand up for your right to use the frequency.
Headphone amplifier is small enough to fit in Altoids tin box, and thanks to low power consumption may be supplied from a single 9V battery.
If you pick the wrong frequency you could interfere with repeaters, point-to-point links or other stuff.
Visit some clubs to get the lay of the airwaves--there are good and bad clubs my experience is that their are more bad clubs than good, which is very sad.
Are we free to use digital and analog with any frequency in these ranges that are not already in use? Der Beat von Berlin 5 a.
Legally you can operate simplex on any frequency that your license class allows and that Part 97 allows as long as you don't cause interference.