Dear Naina,
While you have requested to draft a letter for you but have not provided basic information like what is the nature of the business, what type of this "Holiday Company" is, what kind of tie-up you will have with the hotel and how the hotel will benefit you by tying up with you. Sans this it will be difficult to provide any draft.
Secondly, before sending a proposal letter, it is important to give a call and organise the meeting. Once the meeting is over then it is worthwhile to send a proposal letter. If you send a proposal letter to the unknown client, most probably it could find its way in the trash bin.
While the proposals letters are there for the ages, a new concept is to prepare a video message of 1-2 minutes. Before having a meeting with the client, you may send this message through WA.
Lastly, it is worthwhile to prepare a draft of the letter on one's own and upload it here. Some senior like me will correct it.
Thanks,
Dinesh Divekar