I know that I-10 to I-75 to 429 route very well.
So you will be driving east on I-10? The interchange at 1-10 and I-75 is at Lake City, Florida. The intersection of I-75 and the Florida Turnpike is about 25 minutes south of Ocala. Trust me, you won't miss it.
You will go through two tolls on your way to Disney if you drive the same route I do.
The tolls are as follows:
1. Toll booth on the Florida Turnpike at Leesburg. Toll is $3.00 for 2 axle vehicle; $2.94 if you have a SunPass
2. Toll booth on Independence Parkway (429/192) is $1.50 for 2 axle vehicle; $1.37 with SunPass.
Frankly, unless you think you will be visiting Florida on a regular basis, I wouldn't purchase a SunPass. Yes, they are only $5. But you have to create a SunPass account and provide a credit card to be charged. You can't purchase the mini transponder online (the one that sticks to your windshield). They have to be purchased at an authorized SunPass retailer in Florida - Publix supermarkets, CVS pharmacy, Walgreens. And any Turnpike service plazas, service stations and SunPass service centers.
Hope this helps.