Visiting Disney & Great Wall?

Jessica, unfortunately, your flight itinerary is not eligible for 144 hour visa free transit. Simply speaking, you are not allowed to have two mainland Chinese stops in a row. To be precise, your mainland Chinese stop has to have both immediate points, before and after in two different countries or eligible territories.

It is only 24 hour visa free transit that allows you to travel via China with more than one stop in a row.

To conclude, if you retain your actual flight itinerary you will have to obtain a Chinese visa in advance or if you can, you will alter/adapt your flight itinerary in order to make it eligible for 144 hour visa free transit by inserting a return flight to some third country/territory between Beijing and Shanghai. Fort example, you can do the following:

US - Beijing - Taiwan or South Korea - Shanghai - Hong Kong

This is the only alternative if you do not plan to obtain visas. I'm sorry for bringing you these unfavorable information.

Are there rules about how long you can stay in Hong Kong?
So we are US citizens. Can we do LAX to Paris, then Paris to Shanghai, leave Shanghai within the 144 hours to Hong Kong. Is there a limit of time we can stay in Hong Kong or is it another 144 hours? Then we’d go Hong Kong to LAX.

If you have dropped out Beijing from your flight itinerary, that makes you eligible for 144 hour visa free transit valid for wider Shanghai area and no visa is required.

After Shanghai, you can take ma flight to Hong Kong where you are not limited with 144 hour visa free transit because Hong Kong has separate immigration/visa policy from mainland China. In other words, you can stay in Hong Kong absolutely visa free for up to 90 days.

To conclude, your new itinerary is eligible for 144 hour visa free transit in Shanghai and you can proceed with your entire travel plan visa free and with absolute peace of mind.