The following would be for my hosted website
I would like to offer:
-- a couple service levels (like Budget and Good). For example, a 2 bedroom apartment might be $105 at the budget level with no linens or welcome basket. And $165 might have linens, welcome basket and a stocked fridge.
-- additional services with a minimum stay. For example, a welcome basket if you stay at least 3 days, Free boat rental with at least 6 days, Whatever,
-- several add-ons, like bicycle rental, boat rental or a tour of the area (each with its own price).
-- we discussed this earlier for how to do on an OTA, but how could I package 2 or more adjacent VRs from my hosted website? They would see my 7 VRs. But how could they combine VRs on the website in a straightforward fashion? And have it properly billed (or potentially a small discount).
You can do optional surcharges or discounts that are available on checkout: https://www.ownerreservations.com/blog/enhanced-surcharges-discounts-and-add-ons
For things like the minimum stay, requirement, those would be booking criteria on the surcharge that would limit its application, whether automatic or optional.
If you want more service levels, those could be optional on checkout, either start with the Good level and discount to Budget or vice versa.
In terms of combinations, one booking only applies to one property at this point. If you have commonly rented combinations like both sides of a duplex or adjacent houses, you could create an additional property that represents both of them and allow it to be booked together.