The Adco SFS AquaShed RV Cover # 290-52242 is a great option if you're only seeing short storage or light rain/snow applications but for 6 months of storage in Connecticut I recommend going with the Adco Olefin HD RV Cover # AD67ZR instead because it's a heartier cover with a more durable top for harsher climates.
Attached are some review videos for you to check out. view full answer...
The Power Grip RV Temporary Power Cord Extension w/ Carrying Strap # CAM55197 that you referenced would work as long as you have a 30 amp setup you are trying to extend. This is 50 feet long and has the standard 3 prong 30 amp socket/plug setup so as long as that's what you have you would not need any adapters. view full answer...
Since your 2011 Jayco Jay Feather Ultra Lite X17Z has a # 10 Dexter Torflex axle the only lift kit available for it is the # K71-707-01 is the correct lift kit, and its 2-5/8" lift is the most that is available for your trailer.
If this is not enough lift then reply back with the dimensions of your current jacks and I would be happy to find a shorter jack for you.
I included a video of the # K71-707-01 for you to take a look at. view full answer...
Since trailer tires break down and become unreliable at 5-6 years it would definitely be time to replace what you have now. For a wheel and tire with a great warranty, tread pattern and speed rating the Westlake part # 274-000053 would be a really great option. It's a Load Range D too which means it would have more weight capacity as well. view full answer...