First he is going to need a Bhutan Visa, so he has to apply. Above is an example of a Bhutanese Visa from 2002.
Travel to the Kingdom of Bhutan is highly regulated under the policy "High Value, Low Impact Tourism" in order to minimize the impact on the country's unique society and environment. Bhutanese policy ensures that only a limited number of tourists enter the country at any one time, preventing it from being overwhelmed by mass tourism and thus altering its character, and that the tourists who do come get the most out of their visits.
Visa required in advance
All foreigners (except for citizens of Bangladesh, India, and Maldives) must obtain a visa before visiting Bhutan. If approved, they are given a visa clearance letter, and must present it at the port of entry. The visa is then stamped into their passport. Foreign tourists must use a licensed Bhutanese tour operator or one of their international partners to pre-arrange their visa and book their holiday. A daily fee is also charged for every day of stay. For most foreign tourists, it amounts to $250 a day during tourist high season, and $200 a day for low season.
Discounts also apply for minors and larger groups while surcharges exist for groups smaller than 3. The minimum daily package required for visa processing covers accommodation, food, guide and vehicle with driver. Part of it goes towards free education, free healthcare and poverty alleviation in Bhutan. Licensed tour guides accompany tourists during their trips and arrange accommodations - independent tourism by foreigners (except for citizens of Bangladesh, India, and Maldives) is prohibited.
The only exceptions for having to book a tour as a condition for being allowed to visit are for those who receive a formal invitation to Bhutan from "a citizen of some standing" or a volunteer organization, and those who come as guests of the Bhutanese government.
Restricted areas permit
Upon entering Bhutan, all foreigners are issued a 7 or 14 days "Entry Permit" by default, valid for Thimphu and Paro only. The rest of Bhutan is considered a restricted area, and foreigners need a "Restricted-Area Permit" to enter. Immigration checkpoints are located at important road junctions throughout the country, where police check the permits of all foreigners they find. In addition, foreigners wishing to visit Buddhist temples must obtain a "Temple Permit" from the Ministry of Culture.
While these permits are typically arranged by the tour operators, Indian, Bangladeshi, and Maldivian visitors who did not book through a licensed tour operator must apply for them in person at the Immigration office in Thimphu. The permits can also be extended at the Immigration office in Thimphu for a charge. Citizens of Bangladesh, India, and Maldives are exempt from charges on issuance and extensions of permits.
Looks like it might be a tad difficult to get off the beaten track in Bhutan since it looks like you just can't freely travel around because you have to book a tour with some state-sponsored tour company, unless you have a personal invite from 'someone of some standing', or the monarchy or government......so this is going to prove interesting just getting the clearances to get there.