I did just that last year. Works well !
I'll make a suggestion: Make the outfeed table top a seperate piece. Put carriage bolts under the four corners and that will allow you to adjust the top to be level (or, as I prefer) a little below the level of the saw top.
It has two advantages: You don't have to be so precise when you make the table and you allow adjustment if your floor is not level. My garage slopes from the corners to a central drain.
I also put teflon discs, the sell them at the Borg, under the table to allow me to move it from outfeed to side support.
The one side of the table is pegboard. I use it to store the miter guage spare throat plates, etc for the saw.
Good luck,
Philip