Normally when one is blacklisted due to an overstay the immigration officer has to go through a procedure to add the person to the blacklist and give him a paper w the notice of overstay and a ban of X amount of time. I would suggest trying a different land border before attempting using the airport.
Can you share what shipping company you used in the US and shipping cost?
I used V Pack once to clear customs and went back to them for a second time but the prices were a lot higher for clearing customs. I heard it is best to call ahead and negotiate.
Cambodia land or air is just fine. It all depends how many stamps you have in your passport. If it will be your first or second border bounce you will not have a problem with either.
However DO NOT GO to the Poipet Border.
The other 2 good land borders are in a remote area and I would recomend you get a visa run service to make things easier. If you are new here it will be harder to find a minivan that goes there.
I would not fly to Cambodia (Phnom Penn). The city sucks.
If you want to do a border run by air I would fly to Da Nang (Vietnam) and go visit Hoi An.
If you are looking just to spend the least money as possible I would pick the land border with an agent. Go and come same day.
I also have the 90-day bilateral agreement and extension in Thailand is only 7 days.
Better to exit and come back so you get anoher 90 days
if you are an American you can get the company under your name BUT for the work permit there is no way around it. 4 employees for the WP or 2 if married to a Thai.
It is a shame the government doesn't give the right to work for foreigners married to Thais like in most countries. Very very unfair treatment.
As a start up I would just put the biz under the wife's name, if things take off you can add your name later or do the amenity.
If you are investing a lot of money in the start up I would go the proper way. If you are not investing a lot I would go the easier way.