What your friend needs is called an "open-jaw" ticket. Often available on award seats, sometimes not too pricey on purchased tickets.

I've done this before - rented from Avis or National. One or the other may be doing a one-way special with low (or no) one-way drop-off charges.

I've got bizzare tastes, so I'll leave the "must-sees" and "must-eats" to others.