Born & raised in Lakeland. Lived here most of my life. I'd stay south or north-not east or west unless you're talking towns east or west. I'm talking about actual Lakeland. We're south siders, but nothing wrong with the north side. Once you settle on a place, send me a PM, and I'll give you a heads up about it.
We are currently between houses, so are staying at Sanlan RV Park (south side)for a few weeks. It is extremely nice, but also extremely pricey during the season. The location to shopping, restaurants is tops. I don't know what your winter budget will be. It's definitely worth checking out.
If you are a returning winter visitor, Sanlan has outside storage. Since we won't be a returning winter visitor, we will be looking at outside storage in the next few days. I'll let you know what we find. I've googled and have some in mind, but haven't visited them yet. Again, we'll be staying strictly south side. There is a newer lot on the north side that has covered storage, if you're interested in that. There is no electric - only a trickle cell to charge batteries (for an add-on fee). (We just moved back to Lakeland from a retirement community 25 miles away that had gated, covered storage within the community with metered electric for a very reasonable rate. Boy, were we spoiled.)
If you don't need to be in Lakeland proper, there is a RV Park called Good Life past Bartow headed to Lake Wales on Hwy 60. If you don't mind being about 25 minutes or so from Lakeland, you might check there. Your main shopping would be done mostly in Bartow, I would think. More and bigger options will be in Lakeland as Bartow is a small town. There's also Cypress Campground in Winter Haven that looks nice - Walmart next door and other shopping nearby. Winter Haven is a nice sized town with some shopping/restaurant options. Both of these options are priced much more reasonably than Sanlan.
Any more questions, just ask and I'll try to help.
Gene, Gayle, & Oliver (the dog)
2006 Holiday Rambler Endeavor 40 PDQ/2012 Honda CRV toad
Blue Ox tow bar & base plate/Air Force One braking