color fill segments of a path

Question

I'm designing a board game in Adobe Illustrator for my cultural youth work, and I've drawn the paths that mark the trails of the game where the player can move along:

Now I want to divide that trails into fields, like I've already done in the top right part of the board. The borders of each field are single paths each:

But I need to fill the fields the player can step on with graphics like these:

I know that this can be done by using pattern fills, but since the fields aren't closed paths, they don't have a fill color. How can I tell Illustrator to use the two borders of each field and the segments of the two trail paths to each side to create a closed path for each field? If there are better ways to approach my goals, I'm open to them as well!

Any help is greatly appreciated, thanks in advance!
Lukas ;)

Edit: Using the Shapebuilder tool to create the individual segments seems to work so far. I've loaded my fill graphic as a swatch, and set it as the fill color for the segment, but it creates unnecessary tiling of the graphic, instead of just placing it once:

How can I tell Illustrator to just place it once (and larger)? Edit 2: Figured that out on my own. I was supposed to use the regular scaling tool.

Answer 1

Turn your graphic into a Swatch and then use the Shapebuilder tool.

You can then adjust individual segments by right clicking and choosing the desired attribute such as Scale. Just make sure in the transformation window you select Transform Patterns and deselect Transform Objects

Answer 2

A better way would be to use live paint tool (shortcut key K).

Same process as Ryan suggested turn your graphic into swatch and paint away!

The fill stick to your changes also (If you happen to change paths afterwards.).