I don't have any windows nearby, only a sliding door for the walkout basement. Should I put a hole in the foundation?

Sounds like you could put a hole in the side frame of the sliding glass door near the bottom. Then locate the dehimidifier right next to the door so you don't have a long pipe going across the floor.
To get the water to flow out you might consider setting the dehimidifier on a small stand or table.
Hopefully, the area outside the door slopes away from the house.

Thanks for the assistance. One more question. I assume (almost always a problem) that I drill a 1/2" hole in sill and attach a garden hose to the dehumidifier, running the other end through the hole. Do I need to seal the area around the hose and the hole? If so, what should I use? On the inside or the outside? Thanks again for all the help.

Do you have a washing machine in the basement? You could have the dehumidifier drain into the sink that the washing machine drains into. You would just need to set the dehumidifier on a rack next to the sink.