Among available resources

Villa rentals

Vacanze in Italia, (413) 528-6610, https://www.homeabroad.com.

Hideaways International, (800) 843-4433; https://www.hideaways.com.

Homebase Abroad, (781) 545-5112, https://www.homebaseabroad.com.

At Home in France and Spain, (541) 488-9467, https://www.athomeinfrance.com.

Home exchanges

HomeExchange, (310) 798-3864, https://www.homeexchange.com.

Intervac, (800) 756-4663, https://www.intervacUS.com.

HomeLink International, (800) 638-3841, https://www.HomeLink.org.

Couchsurfing

CouchSurfing Project, (603) 986-0509, https://www.couchsurfing.com.