Sacramento International Airport is a manageable airport for families. The terminals are modern, distances are reasonable, and you have multiple transport options. The main thing to plan for is California's car seat law.
California car seat requirements
California law requires children under 2 to ride in a rear-facing car seat, children under 8 to use a car seat or booster appropriate for their size, and all children under 8 who are shorter than 4 feet 9 inches to use a booster. This applies to taxis, ride-hailing vehicles, and private transfers.
Here is the critical point: Uber and Lyft drivers in California are not required to provide car seats. Taxi drivers are similarly not equipped with them. You must bring your own. If you do not have one, you can request a car seat through Uber (Uber Car Seat option, available in some markets) or book a private transfer and specify the seat requirement in advance.
Terminal facilities for families
Both terminals at SMF have family restrooms and nursing rooms. The airport is clean and reasonably spacious. There are food options in both terminals if you need to feed children before heading out. Free Wi-Fi is available throughout.
Baggage carts are available for a fee if you are managing multiple bags plus children. The walk from the gate to the curb is straightforward in both terminals.
Vehicle options
A standard sedan (Uber, taxi, or transfer) fits two adults, two children, and moderate luggage. If you are traveling with car seats, a stroller, and multiple suitcases, you will need a larger vehicle. Options include Uber XL, a minivan taxi (request one from the dispatcher), or a pre-booked SUV or minivan transfer.
For families of five or more, a pre-booked minivan is the most reliable way to ensure everyone and everything fits comfortably.
Light rail with kids
The SacRT Blue Line is family-friendly in the sense that children under 5 ride free and the fare is only 2.75 USD per person. However, managing car seats, strollers, and bags on public transit with small children is not easy. It is a 45-minute ride with stops. Realistic assessment: light rail works for older children traveling light, not for families with toddlers and heavy luggage.
Recommended approach
Book a private transfer or plan for an Uber XL with your own car seats. Confirm the vehicle size accommodates your luggage. The ride to downtown is only 15 to 25 minutes, so even restless children will manage. If heading to Davis, Folsom, or further, the slightly longer ride makes vehicle comfort more important.