Not made that decision but have travelled for shorter periods. I think you sound like you would like to go, so I say go if your DH is happy enough with that. I wouldn't leave my DH with mine on his own for three weeks while he was working but if he wasn't and was happy with idea I might. I might also arrange grandparents to visit at some point during period.

DH has been away from the kids for three weeks twice now and I wouldn't think twice about him doing that, so providing he was ok with it, I think should also be ok for me to do same if was something I really wanted to do.