you need to be resident there, which you say you are, so you will be honest. They will want to see a flight from there to Thailand and, depending which visa you want, bank statements, maybe proof of address etc etc. I know someone who was in a similar position and applied while still in Thailand as was only going to be back in Chicago for a few weeks.
There’s nothing stopping you applying for the visa online before you get back to the US. You’ll need proof of your address etc from there and the flight details from there to Thailand. It’s all done online so you don’t even need to be there when it’s approved. I understand some Consulates there are quite slow and less than helpful so 2 weeks probably won’t be enough if you wait until you’re home before applying.
Always send in £. Your bank will default to baht so make sure you change it. You’ll get a much better rate if the Thai bank changes the currency. There will be a fee but it isn’t very high.
You can get 30 days Visa Exempt entry when you arrive and extend that for another 30 days for a cost of 1900 baht BUT the airline might insist on seeing a ticket out of Thailand within 30 days when you check-in.
Personally, I’d get the Tourist Visa before travelling which gives you 60 days, especially if you live near the Embassy or a Consulate.