ChesterV advise is good. The rule of thumb for a naked cake is 4 hours maximum of display time. So traveling with a naked cake assembled and display ready is an insurmountable challenge. If you follow ChesterV's advice of packing frozen and toting in coolers your cake should survive.
I find freezing a cake actually makes it moister. I haven't been able to find any science to back that up so it's really anecdotal. But there's a lot of bakers who swear by short-term freezing. Since plastic wrap is no longer air tight, double wrap in plastic, then wrap it in foil. That will keep the cake from absorbing any strange odors from the freezer even if it's only frozen for a short time.
There's a couple of other things you can do to mitigate against a dry cake and/or spoilage.
Buttercream: once chilled, it has to be re-whipped
Swiss meringue and Italian meringue buttercream will only last a couple of days without refrigeration. Once chilled, they need to be re-whipped. So unless you bring a mixer along you're not going to be able to use this type of meringue buttercreams.
There is a variation on the meringue buttercream made with pasteurized eggs. This original recipe was developed by Lauren Kitchen of Fancy Cakes.
Avalon Cake School produced a blog post with Lauren Kitchen's recipe; at the bottom is a note from Lauren Kitchen stating this buttercream can be stored at room temperature for two weeks. While Lauren Kitchen is a nationally known cake baker, and without a doubt is very knowledgeable, I would not leave this buttercream out for two weeks. But I think you can safely leave it out for a few days. There's a few versions of it.
The beauty about this buttercream is you can add just about anything you want into it to flavor it without damaging the texture. So you can mix it with a jar preserve or curd, really whatever you like, to improve the flavor. At the end of Kara's video she mixes in a full jar of curd.
Original Versions posted on sites by Sift by Kara and Avalon Cake School:
http://www.siftbykara.com/single-po...ke-Lauren-Kitchens-Swiss-Merengue-Buttercream
Published on Oct 19, 2014
Lauren Kitchens Swiss Merengue Butter Cream
(Slightly adapted) by Sift by Kara
Beat until smooth, starting on low, then gradually increasing speed until on highest speed
- ½ cup pasteurized egg whites
Add and medium speed for 5 minutes:
Add and beat for 10 minutes till fluffy
- 2 lbs unsalted butter, softened
Add
- 2 tbs vanilla
- 6 pinches of Kosher Salt
Avalon Cake School's original version:
https://avaloncakesschool.com/recipe/easy-and-delicious-lauren-kitchens-buttercream/
Avalon Cake School version 2: better for piping
https://avaloncakesschool.com/recipe/easy-and-delicious-buttercream-v2/
Modified Artisan Cake Company version
http://artisancakecompany.com/recipe/easy-buttercream/
Cake: extending shelf-life
Select a cake with a longer shelf life. Your average sponge cake and butter cake will only last 2-3 days at most without refrigeration. But a pound cake will hold up well for 4 days without refrigeration. Madeira easily holds for 7 days. Madeira is a traditional British sponge cake that is similar to a pound cake.
If you add glycerine to the batter it will help keep your cake moist. Glycerine is normally used in royal icing to prevent a hard set. It's readily available in the big box arts and crafts stores like Michael's and JoAnn's. Glycerine does NOT extend shelf life, it simply slows the rate of moisture loss. It can effect the taste if you use too much, so use sparingly.
Another approach is to use of a natural emulsifier like lecithin. As an emulsifier it improves the quality of your cake crumb. But lecithin has the added benefit of extending shelf life of baked good. It is a readily available product. Health food and vitamin stores have shelves full of it because people use it as a supplement. For baking you only need a small amount.
King Arthur Flour instructs 1-2 tablespoons per 3 cups flour. But that's pretty vague. I would suggest using 20% - 25% by weight per cup of flour.
Cake flour: 1 cup = 114 gram, so 22 to 28 grams of lecithin
All purpose flour 1 cup = 120 grams, so 24 to 30 grams of lecithin
http://www.kingarthurflour.com/shop/items/granular-lecithin-8-oz
You can read an explanation of lecithin on bakerpedia.
http://bakerpedia.com/ingredients/lecithin/