In reply to moorcroft12:
When I first visited 25 years ago maps were dire, but there are loads of good maps available now, of all the main trekking areas in Nepal.
The last time I was in Kathmandu I picked up a nice set published by Nepal Map Publishers Pvt. Ltd. based in Kathmandu, they do several, ie: Everest Base Camp; Around Annapurna; Langtang/Gosainkund/Helambu; Rolwaling/Gaurishankar/Tesi Parcha; Around Manaslu. Scales are between 1:60,000 to 1:125,000. They cost around 500 Nepalese Rupees about four years ago. These are very good maps in full colour with all the additional info you need for trekking. Don't know about Bhutan though, no been yet, still on the wish list.
Enjoy your travels.