Possible to extend stay to 120 days by combining 60 day tourist visa with visa runs and/or 30 day extension?

[csaba81]

If I have a 60 day tourist visa, what are the possible combinations (if any) to extend my stay to 120 days by doing one of the following:

 

1st preference

- 1 border run + 1 30 day extension at immigration office (in which order should these be done?)

 

2nd preference

- 2x border runs to get 30 days each

 

 

[DrJack54]

Tourist visa + extension = 90.

After that border run + extension = 2 months.

+ Another border run.