If you are wanting an awesome experience, trekking the Annapurna Base Camp is great. We just did a great 11 day trek to 4130. It wasn't too strenuous, but had amazing views. We had a great guide and porter from Glacier Adventure Company. Check out Tilak's website if you have any queries on trekking in Nepal. He was a very knowledgeable experienced guide and has a good sense of humour and is very reasonably priced.