(ToddW) I don't anticipate having a big pile of documents, so I will certainly consider a map cover. I had not thought of that; and I'm sure that would be much more secure than a Ziplock bag. I found several options: Granite Gear, ALOKSAK, SealLine, and the Ortlieb brand that (Am_Fear_) recommended.

(Desperado) I like the looks of those "top loading" Pelican cases that you linked. Those are added to my list of considerations.

(Barbakane) That Suze Orman Portfolio system looks interesting; and I like that she includes various forms and info to help you pull everything together.

It's all good...