TLN
Spot on with your thinking.
Have you ben spying on me, coz my setup has both throat mike and waterproof speaker mike! ( there's a nice little Kenwood waterproof mike that I think will fit the 5R.) My mike attaches to the carrying harness though.
Here's a cool pack that I really admire, if it was waterproof it'd be even better. i don't think I'd carry a radio of that value up a mountain without warterproofing! Handset looks like it might be from a Clansman too, don't you think?
http://www.youtube.com/watch?v=Nph5B3CBvno
Batteries. I've been using 3.3Ah 12v burglar alarm batteries as sold by Maplin for the last five years or so. I generally carry a pair of them with me and they work out just fine.
I'm currently working on a fully waterproof and EMC proof upgrade to my man-pack. This is proving to be something of a money pit, mainly because I keep coming up with new and better ways to kit it out. Hopefully it'lll be ready by end August. Fingers crossed :-)