Here is what we have for just that scenario you described!
It is a 3,7m SIB with a 20 hp Suzuki EFI motor on a simple wooden trolley. The boat weighs 100 kg and the motor 44 kg, unless you go for electric start then it is 48 kg. Newer Tohatsu and Mercury weight about the same.
My 15 year old son and his friends walk this down to the beach and back without issues. It is possible to do single-handed but easier with two people.
Unless you absolutely need to be able to fold the boat up a RIB is almost always a much better boat than a SIB. Less maintenance, less weight, longer lifespan, rides better etc. Having said that I really like this SIB and I just sold a smaller 3,2m RIB and kept this.