Ecuador Camera D90 lens recommendations

[Black Tea]

I have decided to buy a D90 at the KEH website. My brother in law is a painter and wishes to branch out into photography.

He will be doing mostly interiors and portraits but as Ecuador is teaming with flora and fauna, he will be doing some outdoor photography.

Do you think he will need a couple of lenses or is one really good one the way to go?

Any advice/recommendations are appreciated.

Also, any other accessories that are must have, like a tripod.

Traveling there in August so I have plenty of time.

Thanks.