Just use your wife's family residence...'I (wife's name and ID card number) will be sponsoring my husband (name) at my family's residence at (address) during his stay in Thailand (Include dates to align with 90 day visa). She signs, dates and includes her contact phone in US. Doesn't need to be in Thai, English is fine.
So taking your proposed 2k a month less rent that leaves you $1340 which is around $45/day, let's say,1500 baht/day, for everything else. Good luck keeping to that budget with a gf tagging along.
You must continue to meet the requirements for the current extension for the full year. The 800k must remain in your account for three months after your extension is approved and must not drop below 400k at any time during the year. It then needs to be back to 800k two months before applying for your next extension. If you failed to do this then you have not met the conditions on which your current extension was approved and therefore won't be able to use monthly transfers.
One thing you're going to find out quick smart is that Thailand's a whole different game to what you're used to back home. The culture, day-to-day life, climate, food, driving, the complexity at times to get the most simple task done, the authorities love of paperwork, the list is endless. Plenty of good informative material available on the likes of YouTube that will give you an insight. You shouldn't have too much difficulty with communication if you stick to the areas where there are plenty Westerners. You'll soon pick up some of the local lingo, make the effort as the Thais will appreciate it. You can check out the official Thai embassy website and see what visas are available should you be wanting to move here long-term.
If you play the drums the countryside might suit better! Seriously though, the best advice is to come over and check out various locations, Remember living here is not like being here on holiday. Hua Hin is a good starting point and would likely be my choice if I were single. Good luck.