Aside from buying actual map cases, are there any other alternatives to Ziplocks for marking maps in UDF?
You could use plastic sheet protectors, or laminate the maps.
an easy way to laminate the map is with clear packing tape.
No ziplock why? If for durability - LOK SAK. A regular map case is good too.
Get a map program like National Geo and print out maps as needed.
They also make a clear coat that water proofs maps.....don't know how good it is.
Also most Office Depots have wide laminators that can take some maps.