Trekking in Nepal with a 300 4 L and others: too heavy?

Has anyone done a 2-3 week trek in Nepal (or, anywhere for that matter) with the 300 4 or 400 5.6, plus several smaller lenses? I have the 24-70 and 135L and want to supplement them with a long prime, but i'm worried about the weight. I'll carry it all (w/my 5d2) in a Lowepro Mini Trekker.

I don't so much want to debate my choice of lenses, but I'd be grateful if anyone could tell me how their back and shoulders held up after a few weeks carrying this sort of weight.

My Sherpa will carry my main pack with clothes etc