OK, I managed to answer my own question, for the most part. Here’s what I did, if anyone cares:
I bought and installed MapCreate7 on my PC. Included with my software was a card reader for MMC cards.
I pulled up my LakeMaster MN map and created a new map of Voyageurs National Park (VNP) and saved it to a new chip (also included in my MapCreate purchase)
I then went to the VNP website and right-clicked on the download link. The file on the website is an .xml file which MapCreate can’t read, so I saved it as a .gpx file by simply changing the file extension in the SaveAs box to .gpx
I then went back into MapCreate and imported the file from where I’d saved it on my hard drive. All the gps coordinates came through, but the different icons did not. I just got red dots for everything, regardless if it was marking a rock, a bouy, a campsite, or whatever.
I’ve tried a few different ways to convert the file so that the icons are retained from the original file, but have not been successful. Unless someone has a better idea, looks like I’ll be converting icons manually.
Anyway, this looks to be the most workable solution to my problem so far.