We are most likely going to roll the dice with a generator. I have had good experiences with them in the past so I hope it hold up.
But, this is the 50' that was recommended to me in the RV community... Your RV will come with 25' already and no one reported needing more than that last year from what I read, FYI.
Camco Heavy Duty RV Auto Extension Cord with PowerGrip Handle, Includes Convenient Carrying Strap - 50ft (10 Gauge, 30 Amp) (55197) https://www.amazon.com/dp/B004809YBE/ref=cm_sw_r_cp_apa_c96UBbE4B439Y
They have 75' cables on Amazon.
So, the requirement for 75 feet worth of power cable is a "Cover the bases" thing.
They state that they cannot guarantee that you will be within 25 feet (standard length of the cable that comes already in the RV) of a plug in point.
It's a heavy-duty cable that is rated for the amperage, and requires specialized connectors for both ends.
Since RV's come (normally) with a 25 foot cable, you just need to bring 50 feet of cable. Which is good, because its kinda heavy.
Now, I only have the 30 amp version, but I purchased this: https://www.amazon.com/gp/product/B004809YBE/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
It worked nicely, and I believe that they make 50 amp variants.
I haven't had to use it yet (3rd year at Camp in an RV), but it's a nice to have and prevents future problems. I've just stored it.
First year, water pump-in/out packages were interesting. Purchasing it gave you 2 tickets that you traded to the people. They came over, attached a hose to your RV and pumped clean water in. Then they attached a vacuum-like tube and sucked the poo out.
Last year... no experience. Apparently it was a scheduling disaster, and was not well advertised when they were "Out" of the service.
I literally posted this thread yesterday:
https://www.reddit.com/r/CampEDC/comments/biwoof/hey_rv_campers_just_a_reminder_if_you_bought_the/
You will need one, they will not have it there for you. The onboard may not be long enough.