You can contact Remington directly to see if they have any parts supply left for the model 1148,or you can attend gunshows,look on the internet,pawn shops,etc.
Gun shop, gun shows, want ads, Shotgun News
www.gunstockinc.com
I have a fairly complete selection of parts for this model. repair@countrygunsmith.net
You can purchase parts for a Ranger model 30 16 gauge shotgun at these locations. Gunbroker, Topgunsupply, Budsgunshop, Gunpartshop and Midwayusa.
Numrich gun parts
Try your local gunsmith. The Riverside is a Stevens shotgun. If you can find out which model it is, you can probably find the wood at Numrich Gunparts
Yellow pages category = GUNSMITHS.
Try e-gunparts.com
That should be a Savage/Springfield Model 18. If you can't find parts from a local gunsmith, try http://www.e-gunparts.com i have a sears roebuck bolt action .410 shotgun model 110.1120 3''. i need the shell ejector piece. to get a clip for a shotgun try marlinguns.com.
Where can you find parts for your Charles daily shotgun
I would start my search at Numrich Gun Parts Corp.
A FEW parts are available from gunpartscorp website.