Very nice looking! The color of the links in your nav bar are very similar. I like to use a reversed-out rollover, like on this page: http://www.bryanray.name/queen/ (Note that I was intending to implement some embedded fonts there, but it never happened). Here's the CSS I used to do that:

a:hover {
background: #CCCCCC;
}

I don't know if you have the ability to edit the actual HTML with Yola or not, but if you can, that might be of help.

Or you could just use a color that's more contrasty.

You should make the big header image a link back to your home page, even though you have a home link. And I don't care much for the "contact me" link being left-justified beneath the rest of the nav links. Actually, that entire navbar should maybe be centered to match the header and the horizontal rule. Contact could either be moved up into the main navbar to replace the redundant Home button. You could possibly make some room by killing the word "maps" where it's unneeded. We assume that most of the pages on a fantasy cartography gallery will, indeed, lead to maps.

I think the featured map "thumbnail" should be larger, and maybe put the description below it. Put your art in the viewer's face immediately. If they like the image, they'll click around for more, and they're likely to read the text. If your primary presentation is text, though, you'll lose a lot of viewers before they've even seen the good stuff. I got some really good advice about portfolio websites from the article "Your Portfolio Repels Jobs" by Jon Jones.

Glad to see you hanging your shingle! Good luck!