It takes downloaded GPX files with no problem. Drag-and-drop simple. Works for routes and geo-caches quite well. I was talking about making my own routes. I have not seen any "free" GPX topo programs out there. There are some free front ends, or transfer programs, but they all want you to buy the mapping software.
Which is fine, Lowrance sells it too. I reviewed what they sent me.
I spend a lot of time in Minnesota and they are big there with the fishing folks. I hope they continue to refine their GPS units towards our use. Competition is good...