(I'm writing this for my husband, so this is my view of the area and our trip)
We went trekking in Nepal's Khumbu area end of October-November 2009 and the weather was perfect, dry, crystal clear mountain views during the day, and very cold at night. (Being so cold at night was the hardest for me, it was like snow camping...) We had just spent 3 months trekking and traveling around Northern India (Ladakh, Spiti Valley, Manali areas) and I definitely felt the elevation in the Khumbu vs Ladakh.
This was our Khumbu trip: flew into Lukla-tea house on river-Namche Bazar(2 nights)-Thyangboche-Pangboche (2 nights)-Chhukung (2 nights)-Dingboche-Lobuche-Gorak Shep (2 nights)-Periche-Lhabrama-Namche Bazar-Manjo-Lukla. I think I have these all right my husband can correct me if wrong...might of mixed them up, but you get the idea. I was happy with what we did and saw. Really enjoyed our extra night stays because I really felt I got to know that place better by staying longer. We were planning on also doing the Gokyo area, but I was done and ready to go back and be warm and rest in India. Have to save something for next time.
Here is a little bit of what I remember of the villages: Namche Bazar has everything you could need/want. Rooms with hot showers, bars, coffee shops, pizza, bakeries etc. and the villages up from there have less and less offered, but I was amazed what was there. Thyangboche monastery had a yummy bakery and a festival around the time we were there, we missed it but would of like to been there for it. Pangboche has nice views of Ama Dablam (my favorite up there) and we rested and stayed in a cozy home there when we did our day hike to Ama base camp. Chhukung, nice ridge to climb up with amazing views, and hike up to Island Lake and peak. Dingboche, yummy bakery and hot showers. Lobuche, feeling the elevation and getting crowed with big groups. Gorak Shep, not much there, few tea/restaurant/guest houses, hike down onto glacier and base camp, early morning hike up for better mountain views. Periche, hot showers, bakery, hospital.
We mostly stayed in the "tea houses" most are just thin wall shacks with one main dining area with a inclosed fire for heat in the middle. I liked staying in the family homes the best. They were a lot warmer, cozy and so interesting to meet locals. The tea houses are all over and you can easily plan and stay in one every night. We did not bring a tent, I only saw a few other solo hikers like ourselves (most everyone seemed to be with an organized group) and only once a couple who had their own tent and slept in it. The cost of a room was usually cheaper than a meal.
The National Geographic Khumbu area map is a nice start and all we needed for the Khumbu area. We also explored Island Peak valley area on our trip, and did a day hike up to Ama Dablam base camp since it was climbing season for Ama. So amazing to see the climbers up there.
We purified our own drinking water with Aquamira and found clear water everywhere no problem. Every guest and tea house sell hot water and I loved taking my metal drinking bottle and having it filled before bed and snuggling with it. We actually did not buy any plastic water bottles on our whole 6 month India and Nepal trip! I saw others using filters and lots of steripens, but we were happy with the aquamira.
I saw showers for sale all over and think they were around $5.00 and the two I had were amazing and very hot!
For clothing it gets very cold, but also can be warm in the lower area during the day. I loved my extra fill down sleeping bag, and would even sleep with my down jacket and thermals on at night when up high.
Talking with others when you get to Kathmandu for recent trail info and tips is easy. I really did not care for the city, there was way too much air pollution for me. But did love all the tasty places to eat (I eat everything especially after 3 months in India. And would not recommend to others this as I did hear of many foreigners getting sick from food in Kathmandu, I know I'm one of the lucky ones).
Tip: If you like the place you stay in the Khumbu ask for recommendations on where you should to stay next, seems like everyone knows everyone up there and can send you to a good spot, some places even called ahead to the next tea house or home and set it up for us (yes they all have phones up there now). It can get busy and crowed that time of year, and most of the group trekking organizations also stay at the tea huts instead of tents up higher.
And if you do end up going on a trip in September I recommend the Ladakh area in Northern India, so much to see and visit in the high mountains.
Wow this is long, hope you find it useful and would love to answer anything else.
Have FUN!!! I'm dreaming and already planing our next trip when our toddler is ready for a Nepal/India trip in a few years...