Fixing some rotten wood, what type of wood should I use ?

Happy Friday everyone,
We've had a soft spot under the drivers side front window of our Lance. I noticed it early last year but just now getting around to fixing it. It's been stored in the barn for the last year to keep the rain off.
I took the window out and have cut out the interior wall panel around the window. Looks like the window must have leaked around the front corner. I'll be pulling off the siding on the outside this weekend to see what all I'll need to rebuild.
My question is what type of wood would be best to rebuild the structure? Is everyone just using good ole Pine or is there something else I should consider?

Thanks in advance.