I've found that my slow cooker has hot spots. Chances are yours does, too. If it does, make yourself a foil collar in your slow cooker to ensure even "baking".
Line slow cooker with a piece of parchment large enough to go up the sides.
Turn slow cooker to warm, and set aside.
To make the rolls, add milk, sugar, yeast, and water to the bowl of a stand mixer fitted with a paddle attachment.
Give it a stir, and then let it sit for 5-10 minutes, or until foamy.
Add in butter, and stir to combine.
Add 2 cups flour and salt.
Switch to dough hook, and knead in.
Continue adding flour in 1/4 cup increments until dough clings to paddle and clears the sides of the bowl. Dough should feel a little sticky but shouldn't stick to your finger if you poke it.
Place dough on a floured surface, and roll out to an 9x13-inch rectangle.
Spread softened butter over dough.
Combine sugars and cinnamon, and sprinkle over butter.
Roll up lengthwise, and gently attach seam.
Cut dough into 12-14 pieces, depending on desired size of cinnamon roll.
Place slightly apart in 5-quart oval slow cooker.
Cover opening with a thin cotton towel, and let sit for 10 minutes.
Turn slow cooker to high, and cover with slow cooker lid.
Cook for approximately 1 1/2 hours.
Remove from slow cooker, and prepare icing.
To make the icing, beat together cream cheese and butter until well-combined.
Add powdered sugar and 2 tablespoons milk.
Continue beating, adding additional milk as necessary to get desired consistency.