OEM parts for '74 Dodge D300 dually

I'm looking to restore my '74 D300. The body is factory w/ rear box and in good shape. The parts I am trying to find would include Windshield, window and windshield seals, firewall wiring harness, wiper motor and related linkage. Plus interior- carpet, roof liner, etc. If anyone has any experience or ideas involving this resto. your advice would be appreciated, Thanks.  

Interior, carpet and headliner is easy. Any upholstery shop can handle that. On the other hand if you're looking for exact stock '74 replacement your odds are pretty slim.  

I'm wondering if I should be able to swap the factory 16.5x 6- 8 bolt wheels for a more common size? And will I need to change brakes? Also is there a database for Production numbers on these vehicles?  

You can use any 8-lug wheel from a 3/4-ton Ford, GMC, or  Chevy on a Dodge. Provided the opening in the center of the wheel is large enough. A Dodge will fit  over a Ford , but sometimes not the other way around. This also means you can switch to a 16 or 17-inch wheel. Try John Gunnel's Dodge book for production numbers, its a maybe.  

And yes, you can use the same brakes.  

Aw crap, I just noticed you said a 300 dually. up front you should be fine,and maybe in the rear. Find a good used wheel shop to compare, or if its in your budget call Frank at Stockton Wheel, there's nothing he can't do to make something work better for your truck with either a new custom made wheel setup or something he might have in used inventory.  

Are there any suggestions out their about wheel tubs for my 48 chevy pu  

Unfortunately I don't have much advice as to where to find parts other than on the internet.  I have found many websites w/resto parts. I am wondering where you found your D300 dually.  I am looking for a 72-74 Dodge D300 dually for my next project and cannot find one.  If you know anybody or any business that has one and would like to sell it I would greatly appreciate some information.  If by some stretch you are currently or EVER interested in selling yours I would be very interested.  

I purchased this truck from my father in 1997, he was the second owner and he bought it from the original Canadian owner in 1980. I've only ever seen one other, but it was in much worse shape. Mine still has the original dealer sticker on the tailgate, which was Ensign Chrysler in Victoria, BC, Canada. It has always been mated with an 11.5' camper. The truck has factory installed camper tie downs on the side of the box and camper shock mounts on top of the front fenders. This truck means an awful lot to me and I probably wouldn't want to part with it. But I'm interested in what you have in mind for your project and if you've done something with another one. I know the rear box is very rare because the boxes were removed so these trucks could be used for tow trucks and other commercial applications.