Moved house with 4 cats

[BlackHillsofDakota]

It's been 2 weeks and 2 days and they are desperate to go out. Yesterday I opened the back door while I was preparing their breakfast and they went out to have a sniff round.
Now it's given them a taste of the outside again and they are desperate to go and explore. I opened the door again this morning but then one of them went under the fence and I freaked out and went and got her and brought her back in.
I know I have to let them go out but any tips to make sure they don't get lost?

I am about to move with 2 and am terrified.
I don't think I will be able to keep them in. They both point blank refuse to use litter.

I have read to only let them.out hungry.

We are planning to try to cat proof some bits of the garden.

I have considered using those car scarers to keep them away from the (very quiet) road.

I'm a nervous wreck we can't cat proof the garden so I know they will be out in the neighbourhood. They do use the litter tray but in this heat with 4 cats I'm changing the litter at least once a day and I can still smell it .
I know I have to bite the bullet and let them out but it's very stressful!

Only let them out hungry and ideally when it's about to rain (unlikely ATM, I know). If you can stick it out to three weeks I imagine they will be OK. Are you near your old house? I imagine they'd be more likely to stray if you are, but I might be wrong.

Expensive but you could get a cat tracker?

One of ours escaped from the tiny top bathroom window within a week of moving, I was so so upset but a couple of hours later he sauntered down the drive very pleased with himself.

I was really surprised that he knew his way back after such a short time.