I saw this recipe just today so I have not tried it YET, but it's so easy I thought anyone RVing could whip it up in no time flat.
Whisk together;
1 can of sweetened condensed milk
1/4 C Key Lime juice (comes in a bottle like lemon juice does)
3 egg yolks
Pour into bought pre-made graham cracker or Oreo pie crust and bake at 350 about 15 mins. or until set.
Cool on counter at least 10 mins. and then put in fridge. Serve with whipped cream and a few fresh raspberries.

Lenora & Choco