Hello,
I've been playing with and collecting radios since I was 6... it amazed me that I could talk into a little plastic box and it would talk back...
Here's the deal... When you play with radios and stuff, you run into legal bull, and performance bull. One thing I hate about certain people in the radio crew is that many of them are rats and will turn your butt in just to be a pain. To them, am FCC license is a license to go out and play vigilante... all that aside, here's my assessment of your best range of walkie talkies...
5 miles? forget it... 7 Miles? a pipe dream... 2 Miles? not with your best 7 mile pipe dream radio. You have about half a dozen things that you have to deal with when you try to get the best performance from radio equipment whether or not it's a portable (walkie talkie), Mobile (in your car) or Desktop (mounted at home with a structure antenna). You deal with...
1) ERP or Effective Radiated Power
2) Antenna height
3) Antenna tuning
4) Battery or Power supply
5) Band and Frequency
6) Surrounding Obstacles including traffic on other frequencies
The lower the frequency, the longer the waves will travel.
The higher the frequency, the the more it will penetrate obstacles and interference.
Using Tone Squelch lowers your range, as does encryption.
The higher the antenna, the longer your waves will travel before it has to deal with earth curvature. UHF travels to the horizon. VHF travels to the Horizon+ approximately 12%. HF (lowband)you can bounce aka signal skip, so you can reach the other side of the world.
You can reach better with 1 watt and a well tuned antenna, than with 100 watts and a badly tuned antenna.
A steady, reliable and FULL power supply is crucial for full ERP performance.
Increasing ERP does not increase range... it increases clarity and readability so that it can be heard. You need to square your power to double your distance. Working with repeaters changes the rules of the game.
Unfortunately, with a walkie talkie, you're sacrificing convenience and portability for negatives on all six factors so your realistic performance in urban terrain with 5 watts with UHF is about 1 mile, VHF, 1/4 mile
The best GMRS radio is the Icom F-21GM which is just as good as getting commercial or Police type Motorola Saber radios programmed to the proper GMRS freq's. It's 4 watts with a relatively well tuned antenna. You can occasionaly find a 5 watt UHF, but you're not getting any significant range for a lot more power drain. It's also repeater capable, CTCSS and DTS squelch... everything you need.
Sorry about going off on a tangent. It might be easier if you asked the questions instead of me going on and on.