Buck Up And Drive! was built using GameMaker Studio and quite easy to mod. For that we'll be using Undertale Mod Tool [github.com]

Download the latest version on the Releases page, unpack it and lets move on.

!!DON'T FORGET TO BACKUP YOUR DATA.WIN!!

Boot up UndertaleModTool (UMT), press File>Open and select data.win in the game's root directory (steamapps\common\Buck Up And Drive!)
Don't panic, UMT will say "this game was built on newer version of GMS and you migh run into issues", don't worry about that, we're gonna just mess around with images.

Billboard related images start from Pageitem 122 in texture page items (and also Pageitem 149 and 150)
After locating whichever billbaord you want to modify. Export the file anywhere on your pc to edit it in Photoshop or any Image Editor program that keeps transparency when saved as .png, you have to export it only once since all billboard use the same Image Resolution.

Here's our billboard PageItem 122, drag, resize or crop whatever pic you want to replace it with.

The game only uses the area where the original billboard picture was set.


After you're done, save your new billboard picture and open UMT, press Import and select your new picture.


Press File>Save and replace data.win in your game directory


Done!

And there we go, like and subscribe, tell your friends and family.