Hey Mark - I don't know 4S Ranch very well, but two places come to mind that are not too far away: Rancho Bernardo Sports Park (I think that's the name), which is right off the 15 freeway - you can see it from the freeway, just to the west, south of Lake Hodges; and Kit Carson Park, which is in Escondido just east of the Westfield North County Mall on Via Rancho Parkway. Both of these parks have large, flat, open fields where you could practice drives. Kit Carson will also have a new disc golf course sometime in the first half of this year.
If you're looking to meet some more golfers, come play in the San Marcos Ice Bowl on Saturday Feb. 13th: http://www.discgolfscene.com/tournaments/3rd_Annual_San_Marcos_Ice_Bowl_2010
$20 to play, lots of fun, prizes and supporting a great charity - The Angel's Depot, a senior citizen food bank.