Justin and I just got back from
Guadalupe River State Park about two weeks ago; we camped for one night camping with our now 13-month-old daughter. We stayed in site #34 which is my favorite site in the park due to its proximity to a hiking trail with bluffs that overlook the Guadalupe River/valley below and with a lot of buffer woods between you and the next campsite. Since your kids are a little older, you might prefer site #26 which has a playground nearby and isn't such a long walk to the restrooms. You can print the
park map out online--it's the same one you'll receive upon entry to the park.
I haven't had time to post a formal trip report yet, but you can read about our trip here ->
Camping w/a 1 Year Old