There is no replaceable gas filter. Since at least 2013 the filter is an integral part of the fuel pump/sending unit in the tank. It should be a "lifetime" filter.
As for the other parts they are identified by the Ford numbers in the maintenance section of the chassis manual you should have gotten as part of the "owners briefcase". If you didn't get it they are available online at:
http://www.fleet.ford.com/partsandservice/owner-manuals/If you need the complete chassis service manual they come up regularly on e bay in the CD version. There are a couple out there now, but the asking price is nearly $300.00. They usually go for between $25.00 and $50.00.
If you decide to go this route be sure to ask the seller if the version for sale includes the F53 chassis. There are many versions available. Some only have the light trucks for the dealers that primarily sell cars. Others have the complete line of trucks for the HD truck garages.
Hikerdogs
2013 Winnebago Adventurer