The most reliable way to know exactly what is included is to check the specific listing for the unit you are booking, since even within one park, an entry-level caravan and a larger, newer model can come with a different standard of inclusions. If in doubt, a quick message to the park before you travel means no surprises when you first step inside.
Because this varies genuinely from park to park and month to month, the most reliable approach is to ask directly when booking an off-season stay exactly what will be open during your specific week, rather than relying on a general summer description of the site. A short call before you travel means you arrive knowing what to expect rather than finding a locked pool on the first morning.
Read the confirmation email properly once it arrives, rather than skimming the subject line. It should carry your arrival window, the unit or pitch number if one is allocated, a contact number for the park office, and any code needed for key collection. Save this somewhere you can find it on the day. Signal at coastal and rural parks can be patchy, and a screenshot beats hunting through an inbox with no bars.
Entertainment is worth a thought too. Most caravans have a television, but streaming apps depend on your own login and a decent wifi or mobile signal, which can be patchy at some coastal and rural self-catering holiday parks, so a couple of books, a pack of cards or a board game is a sensible backup for a quiet evening.
For families, items like a travel cot, highchair or stairgate are sometimes available to hire from the park rather than something you need to bring, so it is worth asking at the booking stage rather than packing something bulky that duplicates what is already on site. The same goes for pet supplies. A food and water bowl is sometimes left in pet-friendly units, but pet food, a lead and any bedding for your dog are down to you.
Inside, look for a wet room or a shower with a level or low-threshold entry rather than a caravan with only a bath, wider doorways through to the bedroom and bathroom, and enough turning space in the bathroom itself to use it comfortably. Grab rails by the toilet and shower, and a bed at a workable height for transferring, are worth asking about specifically if they matter to you, since photographs on a booking page do not always show this level of detail.