Foreigners aren't permitted to buy land in Thailand, but you can buy apartments and condominiums as a non-citizen. Simply put, Thai laws prohibit foreigners from owning land in their own name, although theoretically there is an exception but it is yet to be seen in practice.
if she enters the US on a tourist visa, nothing is stopping her from getting married, and then applying for adjustment of status which allows her to live in the US based on being married to a US citizen until a decision by USCIS is made, that can take up to 2 years. That’s why immigration always scrutinizes those who say their purpose for visiting is to visit a boyfriend, it’s easy for anyone in the US to get married and adjust status then they don’t have to leave.
Its because both of you can get married in the US and then she isnt obligated to return back to Thailand. They are trying to prevent this from happening. It’s better to state the reason as sightseeing only and not for the purpose of traveling to visit a boyfriend.
The problem is you are doing it back-to-back, they see you are stamping out and stamping back in on a visa exempt which is a no-no. Get the 60 day Tourist Visa instead, you can get a re-entry permit and come back in on the same visa with no questions asked.
The 60 day visa is a 60 day visa. What your talking about is extending it for 30 days. Yes you extend a 60 day visa for 30 days giving you 90 days. Yes you extend a visa exempt stamp from 45 days to 75 days. Choose what works best for you. Do you want to stay in Thailand a total of 90 days or 75 days?
Eventually you will get a red stamp in your passport that says you enter too many times on a tourist visa which may deny your application for future tourist visas, and even if you have a tourist visa in your passport, it's up to the I/O to decide if he wants to stamp you in or not, it's not uncommon that they can deny your entry for using too many back to back tourist visas.
You aren’t allowed to work online while living in Thailand on a tourist visa. Immigration still considers that working in Thailand on a tourist visa even if you are not actually going to a physical job. They will deny entry at Suvarnabhumi if you say this upon arrival