This^^^
It will completely change how you view training.
Most training should actually be relatively low intensity but of long duration (like walking in the mountains).
Your body essentially has 2 systems - one for hard work and one for easy work.
What you want to do is make the easy work...
One 4 person tent would probably be lightest and cheapest. With three people the extra room WILL be appreciated.
Hilleberg is great but quite expensive.
You need to ask yourself down or synthetic.
If you're trying to save money, synthetic is probably the move, even though it will be less packable.
Look for the weight of insulation and test how small you can get it with a quality stuff sack
Why not get an older model with the bulletproof 5.7L? I have a 5.7 land cruiser with 175k miles and zero concerns about the motor blowing up or it leaving me stranded.
If the cash is burning a hole in your pocket, spend the money you save on a front end replacement, winch, and suspension...
Key question is whether you want synthetic or natural down, and if you go natural down, whether you want duck or are willing to pay for goose.
If you can answer that, and know what temp range (paying attention to whether you run hot or cold, how warm your tent/sleeping pad is, etc.), you can...