The West Orange trail is probably the best choice for you. There are at least two places in the Winter Garden area that rent bikes, one at KiIlarney Station and another in Winter Garden proper. If you ride west from either of those locations toward Clermont, there are a few hills and some nice scenery. Winter Garden to the end of the trail near Clermont is 15-20 miles.
If you want to ride to downtown Orlando, you can use the Urban Trail to ride between Orlando and Winter Park. The Cady Way trail, a little east of downtown, heads north and east, connecting with the Cross Seminole Trail. The Cross Seminole Trail turns west and crosses I4 to connect with the Wekiva Trail. The Cady Way Trail to the Cross Seminole Trail to the end of the Wekiva Trail is about 60 miles.
If you want to see a little more of rural Central Florida, you can pick up the Gemini Trail in Debary, which is part of the the Coast-to-Coast Trail system. You can ride just about all the way to the east coast beaches from Debary. Debary to the coast is maybe 45 miles.
Another idea to consider is that the SunRail commuter train has a few stops that are within a couple of miles of bike trails, including Lynx Central, Advent Health, Winter Park, Altamonte Springs, Longwood, Lake Mary, Sanford and Debary. Note that SunRail only runs on weekdays.
And, as has been pointed out, there are plenty of other trails in the area.