For trips and clothes, a larger lightweight bag may be good (I use tall kitchen (garbage) bags; waterproof, surprisingly strong, disposable, form fitting, cheap and really make a nice impression at the motel parking lot

).
Cheapo nylon gym bags/duffels.
One big bag that fits the whole saddlebag, packed tight, is a PITA to get out and stuff back in.
Standard valk OE bag liners are available. would not fill the whole Jumbo, and leave room for other things.
http://www.mototourinc.com/valkyrie-saddlebag-linerhttp://www.cruisercustomizing.com/hopnel-saddlebag-liner-for-harley-tourer-honda-valkyrie-yamaha-royal-star-kawasaki-vulcan-voyager/part/BBP-SPLHDTLBut for day to day, I've found a collection of smaller bags work best. Tools, rain gear, small cover, parts, tire repair kit and pump, odds and ends, pistol and loaders. I know what's in each bag, and easier than scrounging through a big bag for little things. Stuff sacks, zipper cases.
I always carry my travel clothes/toiletries in a waterproof duffel
outside the bags on a rack or back seat, so it can go right in the room with no unpacking, and the saddlebag stuff mostly stays on the bike. This one stays dry even on the bottom of a pool. As days go by, dirty, sweaty, wet stuff goes in a tall kitchen bag (repacked inside the duffel when I leave).
http://www.twistedthrottle.com/dryspectm-d38-rigid-waterproof-motorcycle-dry-bag-in-black-grey-or-orange