We flew in and out of Denver, stayed in an Airbnb in Estes Park and spent a week in the area. This is the six-day Rocky Mountain National Park portion of that trip, built around the hikes and activities we actually did.
The pacing matters: Rocky starts high. Start with a small hike and give yourself time to acclimate before the hardest days.
Day 1: Estes Park + an easy acclimation walk
Keep the first day intentionally easy. After driving up from Denver and getting settled in Estes Park, do a casual walk such as Bear Lake or Sprague Lake rather than immediately tackling a long climb.
We also spent time walking the Estes Park Riverwalk and browsing the shops.
Day 2: Bear Lake + Nymph + Dream + Emerald + Lake Haiyaha
This was our combined lake day. Bear Lake itself is a casual walk, then the trail climbs past Nymph and Dream to Emerald Lake. We also added Lake Haiyaha, which may have been our favorite of the easier hikes in the park.

Day 3: Sky Pond
This was our family's favorite hike: hard, long and memorable. The route passes Alberta Falls and The Loch before reaching Timberline Falls. Near the top, the route climbs beside the waterfall. A couple of the teens decided they did not want to do that section and waited below while the rest continued.
We still had snow and ice in mid-June, and some glissading on the descent turned the snow into part of the fun. Start early because afternoon thunderstorms are common in the high country.

Day 4: Ute Trail + Trail Ridge Road + Grand Lake + East Inlet
This was one of the best days of the trip because the scenery changed completely. We hiked the Ute Trail through open tundra with huge views and scattered rocks, then spent time along Trail Ridge Road and the high alpine area.

Continue across the park toward Grand Lake. On the west side we hiked from the East Inlet Trailhead, saw Adams Falls and continued well beyond the falls on East Inlet Trail. Do not think of this as only the tiny walk to the waterfall: continuing into the valley turns it into a real hike.

Day 5: Chasm Lake + horseback riding / Estes Park fun
Chasm Lake was an adults-only hike for us. In our mid-June conditions, the final icy section immediately before the lake was difficult enough that not everyone chose to cross it.
Horseback riding was one of the kids' favorite non-hiking experiences of the week. We also had a lot of fun with bumper cars and the giant slide in Estes Park.
Day 6: Gem Lake + Lumpy Ridge + Estes Park
Gem Lake is on the Lumpy Ridge side of the park and feels different again. There is plenty of elevation gain, big rock formations and lots of terrain that made us want to climb around and explore.

And then there is the toilet. The backcountry privy on this trail has an unexpectedly spectacular mountain view.

If you have an extra day
We also spent a day doing activities in Denver. It is easy to add Denver at the beginning or end of a full week.
Two additional hikes to consider
Mills Lake: a good option if you want Glacier Gorge scenery but do not want the full difficulty or waterfall climb of Sky Pond.
Ouzel Falls in Wild Basin: a moderate waterfall hike in another section of the park and a good way to see more of RMNP.
Important planning notes
Altitude: start easier than you think you need to.
Weather: start major hikes early. Afternoon thunderstorms and lightning are a real high-country hazard.
June conditions: do not assume June means snow-free trails.
Timed entry: current summer access uses timed entry, including a separate Bear Lake Road option. Verify current NPS rules before your trip.
Why we organized the trip this way
The itinerary alternates terrain and effort instead of stacking six similar hiking days. The Bear Lake lake circuit gets everyone moving at elevation without the commitment of Sky Pond. Sky Pond then becomes the big family objective. The next day changes the scenery completely with tundra and the west side. Chasm can be a strong-hiker day while others choose activities, and Gem Lake finishes with a shorter but still worthwhile climb.
Approximate hiking difficulty by day
Day 1: Easy. Keep the walk short and use the day to acclimate.
Day 2: Moderate. Multiple lakes, but easy to shorten if someone is feeling the altitude.
Day 3: Hard. Roughly 9 to 10 miles for Sky Pond with the Timberline Falls scramble.
Day 4: Flexible. Ute Trail plus short alpine walks and as much East Inlet as your group wants.
Day 5: Hard for Chasm Lake; easy to moderate for the horseback-riding/activity alternative.
Day 6: Moderate. Gem Lake is short but gains roughly 1,000 feet.
What we would reserve first
Start with lodging in Estes Park, then work backward from the park's current timed-entry system. Bear Lake Road access matters for the lake circuit and Sky Pond, while other days use different parts of the park. Horseback riding is another activity worth reserving ahead during busy periods.
Build weather flexibility into the week
Do not become so attached to the day numbers that you hike Sky Pond or Chasm into a bad forecast. If the best high-country weather falls on Day 4 instead of Day 3, swap the days. Gem Lake, Estes Park activities and the lower-elevation pieces are much easier to move around than the major alpine hikes.
One car or shuttle?
We like having a car for a trip like this because Trail Ridge Road, Grand Lake, Lumpy Ridge and Estes Park are spread out. For Bear Lake Road, however, the park shuttle can solve the parking problem even when you have a car. Think of the shuttle as a trailhead strategy rather than a replacement for having transportation for the entire trip.
Beyond the Overlook