the single entry tourist visa for 60 days is going to be your cheapest and best option. No messing around at immigration if you took option 1 and no need for a full day in a cramped bus if you took option 3.
Only visa exemptions ON LAND BORDERS are limited. You could, technically fly in and out a million times. That's not restricted but eventually you may be asked. Tourist visas DO NOT COUNT as a land crossing, so again, technically you could cross land borders a million times if you obtained a TV before entry.
You can fly out then back in as many times as you want. Some seem to get questioned at arrivals but there's technically no limit on it. That gets you the 30 days and then you extend 30 more.