A: welcome to my house 24/7
B: We'll definitely take you up on that.
What is the meaning of "take you up on that"?
It means accept someone's offer for something.
You are welcome to come visit me.
I just may take you up on that = I may accept your offer to visit you.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.