Plan to do a trip to Bhutan with family i.e. my wife and 3 grown up kids ( in 30's) . Last year I went alone to Nepal one month and trekked to Thame (4000metres ) and loved it.
In bhutan would like to do a small private tour for the 5 of us. The rest of the family are very much into meditation and bhudist philosophy so would really like to incorporate that.
Would also like to do some trekking of moderate degree (Probably only for say 5 days ) but ideally being able to stay in teahouses along the way rather than camping i.e. having some comforts like shower and western type toilet---I managed to find those trekking in everest region and annapurna.
Would also like to experience a festival while there so any ideas when they are.
What is best time to go---probably April--June or Oct--dec??
Any advice appreciated

As you may already be aware, you have to use a local Bhutanese agency to arrange your trip. You can contact an agent in your own country, but they will have to subcontract with a local agency and it will cost you more and complicate your communication with the agency that will be making your arrangements.

I'd suggest you start with a good guidebook, then contact a few agencies with your wishes. There have been a number of trip reports on Bhutan here - of to the top of the page and from the "view by country" drop-down, choose Bhutan.

A good place to start is with the Tourism Council of Bhutan's website, which has a list of Bhutanese tour companies, suggestions for types of tours, place to visit, etc. http://www.tourism.gov.bt Your tour company will arrange your visa and book your hotels but you can get a good idea of the hotels available at http://www.hotel.bt

All tours are custom tours, just let your company know what your interests are and they will accommodate you. Unfortunately, there aren't any teahouses along the trails in Bhutan. You'll have tents (including the toilet tent) horsemen to carry your gear, a cook, etc. I'm also partial to hot showers and have taken long day hikes along parts of some treks but haven't yet taken a trek.

I've traveled to Bhutan 4 times (May, June, July, December) and prefer December for the clear mountain views (sometimes obscured by clouds and rain in June & July ), the lower rates, and for far fewer tourists, even at the festivals (Trongsa's festival is in Dec-Jan and we saw a local festival as well). Oct-Nov is also a good time for festivals.

We went late October - early November and caught the festivals in the less touristed Bumthang Valley. It was warm during the day and cool to cold in the evenings. Don't know much about trekking, but our agency, Snow White Tours was excellent and will customize for you. Contact is Kencho.

thanks to all of you for some ideas that I will follow up on---sounds pretty exciting