A website does not have a specific number of pages to have, to improve its referencing and the ease for the customer to browse it. The quality of a website is mainly measured by the quality of the content than by the quantity.
However, it is interesting to note that companies with websites containing 51 to 100 pages generate 48% more traffic than companies with sites containing 1 to 50 pages.
For the site of a hotel, some pages are essential:
The main pages (rooms, rates, services, location) should be directly accessible from the menu so that the user looking for specific information can reach them easily and with as few clicks as possible.
Depending on the hotel's typical clientele, foreign language versions of the website should also be easily accessible.
Other pages are optional but essential for your site to be correctly visible on the Internet. Google will highlight the sites that will have the best SEO.
To get a good referencing you can for example create a blog on the activities of your city and region or on local events and include in your pages links to partner sites.