Suggestion: take the planet of least value in the Sol system and convert it into a safe zone and trade hub. It should be in range where any new player can take advantage of it and a useless enough planet/moon where it's not worth clearing out. This will allow for set trade routes to give people with nothing more than a hauler ship something to do to make money as well as give people a place to buy and sell items, materials, etc.
This is more or less a re-suggestion of the Callisto post.
Secondarily, I'd suggest having a total power limit in order to mine in Sol and limit owned planets to 1 (or half of one for the asteroid belt and jupiter) to give all the active new people somewhere to get started. I'm pretty new and even I can afford to mine outside of sol, and tbh most of the valuable stuff is outside of sol, so it seems reasonable. Have a mining treaty (claiming first mining spot on planet sounds good) to protect the little guys, enforced by bigger members.
this is lokk hauser (not the architect dude in the introduce yourself), I've set one up near Mars. I'd ask Caker18 and SPQNR (as is our official corp policy) to keep their squabbles out of our Mars base