You can take Amber to town and Karen can come back for the car.

You tell them you could give them a ride back. "But what about my car?" Amber asks. You were waiting for the question and wanted one of them to ask it.

"Leave your car keys in the ashtray. Karen and I will come back, and after these cars are gone she can drive it back", you reply.

"But she only has a permit and isn't on my insurance", Amber counters.

"You have a nice car and by the time the owners of these cars move them, the cops will be looking more for Grandpa speeding to church than a respectable girl driving a normal car." She agrees to your plan. You text your friends that the van is gone but you will be back for them.

You wouldn't bother at all except that you guys sometimes take girls back to the van as a last resort (it really is a piece of shit). You drop Amber off at Karen's house as that is where she was supposed to have been all night. You drive a mile down the road and stop. You have a bottle of booze hidden. You get it out and offer Karen a swig. She gladly takes a few swigs and says she needed that as while she loves her cousin, she can be a lot to handle at times.

You take seldom traveled back roads and pass the bottle back and forth. After about half the bottle is gone her eyes are glossy (you took small sips and being bigger than her are still somewhat sober). You get a text from your best friend Bobby asking where the sleeping bags are (code for need the van for fucking). You are still about 15 minutes out from the Smith's as you have been driving slow and taking the long way and working on Karen. She is primed and ready for fucking (you have four sleeping bags in the back). Do you head straight to the party or keep the party of two?