Is there still a difference if you do a visa run over land or via air?Your best bet is a double entry tourist visa available from your local Thai consulate.
Enter Thailand with it ( good for 60 days), extendable for another 30 days while in Thailand . I believe the price for the extension is 1900 baht. At the end of 90 days do a visa run. Re-enter the country, you will get another 60 day stamp. Extend again and you have your 6 months.