Don't send that thing off on a six week trip. Fix it yourself!
I have a Pietta 1860 Army. First the main spring broke. I had already had the handle apart, so that was pretty easy. I sent off for a new spring [free under warranty] and put it in in five minutes. In fact, it was too stiff, so I ground it down with a belt sander until it was right. It works fine.
Then the hand spring broke. I sent off for one [again free]. I was intimidated by this, as I had to get into the guts of the gun. Believe me, it is pretty simple to take these things apart. I fixed the hand in ten minutes.
As far as your loading lever falling off, you just have to keep an eye on the screws, they will work loose.
The front sight, I am not sure. I had a civil war rifle, and I put a new front sight on it. I simply soldered it in place with a propane torch, and plumbing solder, stuff you can buy at K Mart for ten bucks.
Pietta has a repair kit with a spare main spring, hand and spring etc. Send off for one of those kits and become your own gunsmith.
I was posting up on this forum a few months ago about how I was intimidated about taking the gun apart and a 13 year old kid [the smartass] got on here and said he takes his apart all the time. You can do it too.