Just an observation and a suggestion.
Perhaps we are making too much of the "suggested 6 to 8 encounters per day" line, and not enough of the recommended encounter XP per day budget.
Look at it this way...a dungeon with 8 rooms* might be considered an 8 encounter day, even though only 4 or 5 of those rooms actually include dangerous monsters or encounter level traps to fight (the other rooms consisting of color, treasure, or puzzles which tax player brains but not character resources). Encounters have never been defined exclusively as combats.
So if we instead decide to focus on the daily xp budget, we can easily meet that with 3 to 4 hard to deadly encounters.
When I'm designing an AD, I use the DXP budget to determine how much the party could face and accomplish their primary objective, but the day itself I design over the DXP limit. It is then up to the players to look for ways to avoid encounters to ensure they can get to their main goal. I'll then determine which encounters (if any) can't be avoided, think of some ways the others could be (though leave options open for whatever crazy stuff the party may come up with) and try to get a sense for what the party may be able to do in combat with excellent tactics. Note that if the party is optimized for combat, they will be able to handle a higher DXP budget.
So if my party of 5 has a DXP of 10,000, and the objective is to sneak into a castle and rescue a princess scheduled for termination I might design to the following.
6,000 - Minimum encounter level to accomplish objective (start with 3 separate unavoidable encounters)
10,000 - Average xp of encounters party can deal with in combat (add 2-3 encounters with Hard DCs to avoid)
12,500 - Good tactic/Lucky rolls budget (add 1-2 encounters with Medium DCs to avoid)
16,500 - Total Encounter XP on the board (add 1-2 encounters with Easy DCs to avoid, but with possibility of Deadly individual encounter if they don't, this is where I also like to tempt players with a shiny treasure to entice them into a combat that won't help them with their primary objective, but may provide some other benefit)
The other advantage of designing this way is that if players have unlucky rolls to start the day in a combat or two, they still have a path to victory if they can figure their way around some of the encounter difficulty.
To be clear, I don't design every single session to this, but instead I use whenever the players are heading into a major objective. Typically that's once or twice per character level.