Will meet or is meeting

Try not to think of it strictly as RIGHT VS WRONG.

IF you had to choose on the GMAT between these two options, then you want to choose:

"The governor WILL MEET Ron for lunch tomorrow."

This is simply a variation of the "to do X" vs "doing X" that we covered in depth with various OG and GMATPrep examples here:
gmat-pill-presents-vs-which-to-choose-a-secret-idiomatic-152791.html#p1224932

The way we like to think of it here at GMAT Pill is what is PREFERRED by the GMAT folks.

IF we had to choose between those 2 options, then we choose the option above-----NOT because the other option is WRONG, but rather because the correct option is the PREFERRED option on the GMAT.

If you were NOT given both options to choose from but instead were given:

"The governor IS MEETING Ron for lunch tomorrow." - you should NOT think of this as WRONG. By itself, it's actually fine.

It's just that when you put it next to the other WILL MEET option --- the -ING form is NOT PREFERRED.

Again, for more examples, please reference the article here: gmat-pill-presents-vs-which-to-choose-a-secret-idiomatic-152791.html#p1224932