Oregon where to base camp

It’s all dependent on “exactly” what variety of material you’re looking for. For sunstones, just go to the mines and pay. I’m in prineville. Where are you located out of?

When looking for jasper, agates, obsidian. Its best to have an Idea of what kinds you're looking for. I dont say this in a snarky way, but more for a clarification to try to assist you. Saying you want to look for jaspers/obsidian encompasses a large area. Glass buttes has obsidian, but there are different beds out there if you're looking for specific types. If you wanted agate limb casts then youd want to go to congelton hollow out in paulina. If you wanted moss agate, then try the maury moss beds. If you want to find various agates, crystals, woods, jaspers with no distinct deposit, then bear creek is a good place. If you want green jasper petrified wood, then youd want to go look for hampton butte wood. Hope that clears some things up. I know places but knowing the distinct materials you're wanting to obtain would help me better guide you.  

Best base camp would be in the realrockhound driveway, from what I hear.
For sunstones there are like 3 claims that offer a good pay to dig experience. You will likely find some small clear stones in the public area, but not so easy to find color.
I think if I were to have the time and do a loop, maybe start by dropping through WA and visiting Saddle Mt for Pet Wood, then south into Oregon, through Rufus to Madras, with a stop at the Polkadot Agate mine and Richardsons Rock Ranch for sure. There will be a show with field trips in Prineville starting June 13 if that fits your schedule, also one in Madras the following weekend. From Prineville you could go through Redmond and Bend to the sunstones, with the all important stop at the peterson rock garden, and see Crater Lake if that's of interest. After Sunstones would probably be Hart Mt for jasper if you can find it, and you could go on to McDermitt for a number of things, then north up US95 with tons of spots to look. At I84 you could head east to Tony's but you want to message him your itinerary ahead of time. Chris can host visitors if he is out getting another estate.

Rockoonz gave you some good advice. As far as base camp, if you want to stay in a hotel, prineville. If you’re camping, Hampton butte is a good central point. Then you’re 30 min to an 1hr in any direction around you to find material in the are. There isn’t much for picture jasper in central Oregon. Vistaite is the only picture jasper close to prineville and it’s basically mined out of existence. It can still be found, but scarce and requires lots of knowledge on the area of where and how to dig. The fire obsidian is on a claim.

You can reserve a spot at the ochoco reservoir in prineville. You can kayak there. Across the road up in the rim rocks is the batcaves where jasper can still be found. About a 20 minute hike from your spot at the reservoir