I think we have a PA regional forum. If we dont we should make one. See about joining that forum and you might be able to find a reefer that is somewhat local to your area that would be willing to give you a few cups of their sandbed.
You can seed your sand with live rock. Of course this process will take the longest to produce a healthy population of sand bed critters.
There are some places online that sell sand bed detrivore kits. You can get one of these kits that usually include worms and mini starfish, pods
and the like.
Is there a reason you dont have the live rock? Are you just looking for a vendor for the live rock or do you not like its apperance? Adding a fair amount of good quality live rock will eventually seed your sandbed.