It is better not to take a local Kathmandu bus, because they are usually dirty and overcrowded. It is more convenient to ask the hotel for a reliable taxi service.
Be careful to arrange for the taxi to wait for you while you are in the Pashupatinath, because taking a local taxi for the return trip will cost you several times more.
Getting to Pashupatinath and back from Kathmandu city center by a taxi will cost around 15$, including the waiting cost.
Hiring a guide will cost about 10$, it is well worth the money since you really get explanations of the rituals and traditions of Pashupatinath.
To enter the site of the temple a foreigner needs to pay an entrance fee of 1,000 Nepalese rupees (about $10 USD).
The site is open every day from 4 AM to 9 PM but it is closed in the middle of the day between noon and 5 PM. The best time to visit the temple is early in the morning or late in the evening. One should reserve about 90 or 120 minutes to visit it.