since i'm just an old "city wimp", i can't offer any advice about service of your septic tank.
however, from growing up in a house with one, i can offer this : make sure it is well marked !
one, so you don't have to dig up the whole back 40 to find it when it needs pumped.
and two, so you don't drive over it with heavy stuff, like tractors.
i remember these things happening during my "yout", and learning cool bad words from my dad, uncles, and grandpa.