Rehydrating dehydrated food?

I'm looking to purchase a dehydrator shortly and had a few questions related to the food?
Once the food is dehydrated, foods like mince, dahl and vegetable type foods, how long will it store for in a freezer? And how long will it store for out of the freezer?
When rehydrating the food does it need to be simmered or can I add boiling water and let it sit for a period of time? This question is related to the kind of cooking system that will be most appropriate. I have my eye on something that is light, very economical, boils very well but won't simmer!
I"m also looking for some tips on lunch foods, something that can be prepared and eaten with a minimal fuss, as lunch is always in the middle of the hike and I don't want to fuss too much!
Cheers!
Once the food is dehydrated, foods like mince, dahl and vegetable type foods, how long will it store for in a freezer? And how long will it store for out of the freezer?
When rehydrating the food does it need to be simmered or can I add boiling water and let it sit for a period of time? This question is related to the kind of cooking system that will be most appropriate. I have my eye on something that is light, very economical, boils very well but won't simmer!
I"m also looking for some tips on lunch foods, something that can be prepared and eaten with a minimal fuss, as lunch is always in the middle of the hike and I don't want to fuss too much!
Cheers!