It's difficult when you're not in your own place. been there done that too many times. Although mother in law was never difficult to live with.
Personally, if you feel the need to get out and enjoy the day, get your fanny outside and enjoy it. If difficult child II doesn't like it, he can lump it. He can only spoil it if you let him. And giving in to such behavior only makes it worse.
Is there a park nearby? Maybe one with woods and a creek? Then he could have fun doing something guyish while you're out enjoying the day.
As for myself............I've been doing MUCH needed gardening on this so far 79 degree day. Taking advantage of the weather. And guess where grandson Darrin is?? Right there pulling and digging out weeds next to Nana.
Fortunately, he's still at the age where helping is tons of fun.
At the moment we're on a lunch break.
Oh, and even while working hard you can have fun.......Darrin's bug container now holds tons of Holy Moly's (rolly pollies), several crickets, and a snail.
((hugs))