As has been said, no problem taking knives, saws or axes in rucksacks as part of your checked in baggage on Ryan Air. I have just come back from my second Norway trip this summer, both via Stansted/Torp, and there were no problems for either trip. No one in our expedition of 7 had a problem.
Be aware that they may still have increased security when you go and take steps to prepare your baggage accordingly, this only applies on the outward journey. Carry on was permitted, but it had to be no bigger than 16x35x45cm, this was STRICTLY inforced and there were a lot of folks being turned away to go check in their bags, pay excess baggage etc. If you have things like billy cans in carry on, no problem, just take them out so they can be x-rayed outside your bag. The same goes for electronics, if you bunch all cameras, torches, etc in a clear bag and have them run through the scanner outside your main carry on, passing through security is a breeze (even though they were x-raying shoes, and giving everyone a pat-down).
We were in Vassfaret last week. There were mushrooms everywhere, loads of boletus (Ceps, slippery Jack I think, or another similar in colour, size etc) They were however mostly past their best due to heavy rain just before we arrived. The place was loaded with blueberrys and lingon (cow) berrys which we had in bannock. The fishing was very poor where we were and out of 5 people giving it a try only me and one other bloke got anything. The normal rules of fishing still apply! Even at the right time of year, the weather can be wrong, or there may be no fish where you are. So be careful about banking on catching dinner! While I am sure Torjus could have found more to eat up in the mountains, there wasn't a lot of bio-diversity where we were and I think you would have been hard pressed to find anything other than fungi, berrys and fish.
The Norwegians seem pretty layed back about bringing food into the country, there were no signs saying that you couldn't, unlike here in the UK. In either case freeze dried stuff is going to be fine. Its the fresh meat/fruit/veg/dairy that causes problems normally.
Shopping wise, ilovemybed probably did more than me, but on this last trip we went and had a look in a couple places, including a large Co-Op. Whould you believe that Norwegian Co-Ops sell Mora knives, Fiskars and Hultafors axes, Eagle brand camping kettles, fire stands and so forth? We also went to some kind of General store which sold Mora by the bucket for about £3.50 and Whettling(sic) axes for about £26. This kind of kit is pretty cheap there. Its just the food, clothing, petrol, and beer that is expensive!....oh yeah, you can't get alcohol in food stores, only in state run liquor stores.
Insurance wise, I got a good deal with Barclays travel insurance. I got a year's worth, that covered for hiking, canoeing and such, anywhere in Europe, for about £35. It covers me to be rescued and everything I don't know what the services are like in Norway, but thought it a good idea to have.
Hope you have a good trip! I am sure that you have your kit well sorted. On our trip with Torjus we all carried too much stuff. On the one a week ago weight wasn't an issue, but it was already getting damned cold at night, a damp cold.
Being lost is a state of mind, not a state of place.