The Summer Palace and the Great Wall are both worthwhile Beijing experiences, but they reward very different kinds of time. The Summer Palace asks you to wander; the Great Wall asks you to travel farther and walk with purpose. Combining them in one day can work, but only when you accept that neither stop will be a full, unhurried visit.
When the combination works
This is a reasonable one-day plan for travelers with limited days in Beijing, a reliable early start, and a preference for seeing two landmark experiences rather than deeply exploring one. A private driver helps because it removes the most fragile part of the schedule: getting from the city-side attraction to the wall without a chain of transfers.

Start with the Summer Palace when your hotel and energy make that natural, then choose one wall section and a modest walking goal. Do not try to add the Forbidden City as well: our Forbidden City and Great Wall guide explains why a two-major-site day already needs tradeoffs.
What you need to give up
On a combined day, the Summer Palace should be a selected walk, not every hall and garden. At the wall, aim for a meaningful section rather than the longest route. If you want a flexible full experience at Mutianyu, use the dedicated Mutianyu planning guide and give it its own day.

Driver, guide, or DIY?
A private driver is the practical choice when combining these two places because it protects time between them and gives the group a fixed return plan. A guide is useful if historical context matters at either site; otherwise driver-only service may be enough. Compare the options in driver-only versus guide service.
Choose two days instead when
Split the itinerary when you are traveling with children or seniors, want serious photography time, or simply want the wall to feel like a destination rather than a deadline. A calm Great Wall day also needs water, good shoes, and a realistic walking goal; use the packing checklist as a final preparation step.
The best version of this combo is selective: one focused Summer Palace walk, direct transport, one practical wall section, and no pressure to “complete” either attraction. If that feels rushed before you book, make it a two-day plan.