Sorry, but first question I just gotta know - is there any special meaning to your name that you choose for this forum?
Anyhow, as to your questions:
1. Propane - will vary: by provider, if you own or rent tank, amount purchased, etc. Best is to contact a number of them in the area...
2. Septic system - for me, in all the houses I've owned [5], all have had septic or lagoon; like any system, properly maintained, will provide many years of trouble-free [free being relative in some cases] service.
3. Wells - only 1 of the properties was on city water; and that to me was worse... can not stand the Chlorine, Flouride, etc. additives/treatments. Like the septic, if properly installed [drilled & set], w/ a good bladder, you should have no troubles at all. Of course, as w/ any water system, good to have it checked before buying and then periodically.
Seriously - don't be 'scared' of such systems [well, septic, propane]; just have a [few] reputable inspectors go over them with diligence, and see what needs to be done [if anything] after their report. Then be scared if they recommend many changes, and their relative or friend Bubba Joe can fix 'er up just right for a very good non-advertised price...
As to where to look at, some areas that are at times overlooked could be in the Kimmswick and then south of there, towards Herculaneum. Your 30 minute region would include from Herky, to Cedar Hill, and then over to Pacific - all relatively 'rural' type areas in places.