New amateur designer

Having just read through the rules but not actually playing it, I think I have a strong understanding. The one thing I'm confused about is action points. Tell me if I'm wrong, but it seems to me that at the start of a players turn they roll 2 six sided dice and the total is the amount of action points you have for the turn.

Clearly this is a light, fun game that's easy to learn but I fear that a player who simply gets really good rolls wins (if my rules understanding is accurate). If it is, I have a suggestion:

Create a custom die. That die might have sides like: gain 3 ap and 1 gp, gain 1 ap and 3gp, etc. Make three of these. A players rolls all three and then must choose which one they'd like to have for the turn. This method changes dice rolls from "roll 2 sixes for profit" to "which option works best for me?" That's a more dynamic system that encourages thought and strategy.

You could even take it a step further and have the losing player roll X+1 dice, where X = the number of players, and have the losing player pick which die they want first, second to last pick next, etc. This system auto balances the game to make it closer, helping to prevent runaway leaders. (X+1 is so that even the winner still has a choice to make). Although it may be hard to determine who is "last" if multiple players occupy the same step.

Thematically, I don't like that desert, jungle, ice, and swamp all function identically. It neuters the "unpredictable" race track setup.

I hope this helps!

You might want to reconsider adding mechanics specifically meant to frustrate. Variance will always tip the scales towards certain players. I like to minimize how much randomness negatively affects players without eliminating it completely. I like variance that gives players options.

I don't think that's a bad idea at all, but it doesn't fix your dice problem.