This week I belatedly was trying to find a campsite at Tumalo State Park in July and found all the serviced sites were already reserved and a search for a trailer site showed no result, however I noticed that tent sites were still available. I wrote to Oregon State Parks asking if it was permissible to use one of these sites since our vehicle and trailer would fit on the driveway. I received a quick reply:
Campsites in the Oregon State Parks are multi-purpose if:
1. The campsite driveway is long enough for both the trailer and truck that is towing it.
2. There are no site alerts indicating no RV's or trailers allowed or the site is angled or otherwise not suitable for a trailer or RV.
3. Tents must fit on the tent pad area of the site.
Based on this I made a reservation without difficulty. I was impressed with the speed of the answer from Oregon State Parks!