Wow, go for it! Never been but envy you the chance, Ulan Bator, you'll love dropping 'that' name as a place you've been. Lucky you.

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The main question would be as to how long your husband will be spending in Ulaan Baatar. At the end of a week you might easily be more than ready to go home, since the city's main attractions are not very numerous, and getting out into the countryside (Mongolia is really a giant paddock disguised as a country) can be difficult to arrange because of fuel shortages. Trips out really need to be booked in advance.

I know of one reliable guide who might show you around if she's not too busy. Otherwise you might look at the site of Karakorum Expeditions Mongolia, which might give you some idea of the situation:

http://www.gomongolia.com

I only used these people for minimal assistance, but they were very helpful. The company is owned and run by Australians, and is reported to be reliable and efficient.

I liked Ulaan Baatar very much which I visited about two years ago, and I hope to return.

Peter N-H
http://members.axion.net/~pnh/China.html