Tireding Holiday

Tired Holiday - the holiday itself felt tired
Tiring Holiday - the holiday made you and/or someone else feel tired

I felt more tired during the past three days than during my (regular) work days.

alternative:
The past three vacation days were more tiring than regular workdays.

On May 1st, it took me and my friends three times as long as normal to {arrive at the hike destination| to reach} {the hiking place | the trailhead}.

The “hike destination” would be the ending point of your hike - 徒步的目的地 - so “it took us three times as long to arrive at the hike destination” means the hike itself took three times as long.

A “trailhead” is a starting point on a hiking trail or path. On long trails there might be many trailheads - access points where you can get onto the trail.

At first, I kept calm down because it was the normal situation on national holidays.

suggestion: At first I kept calm because heavy traffic was normal for a national holiday.

After trying to comforting her several times, I felt tired and just let it go.

I changed “comforting” to “trying to comfort” because “comforting her” implies that you succeeded in making her feel better, but the fact that you had to do it several times implies that your attempts to comfort her didn’t really succeed, so “trying to comfort her” makes more sense.

I'll take a stroll in the parks and look at the flowers, and then go back home to sort out the videos and photos on my phone.

I sorted out some out last night.

more natural

I have uploaded two videos aboutfrom my hike in / on Baiyunshan on / to my YouTube channel.

“About” feels wrong because the videos don’t describe anything about the hike. They depict scenes from the hike.

Tireding Holiday

I felt more tired duringover the past three days than during my work day.

"during the past three days" is probably grammatically correct, but "over the past three days" sounds more natural.

On May 1st, it took me and my friends three times as long to arrive at the hikeing destination.

For more clarity, you may also consider writing "it took me and my friends three times longer than usual"

At first, I kcould keept calm down because it was the normal situation on national holidays.

Looking at the native text, I'd suggest the addition of "could" here, because "还能" implies an ability to keep calm.

After comforting her several times, I felgot tired and just let it go.

"got" would be the better choice of word here, as it suggests a causal relationship: it was the act of comforting your friend that caused you to feel tired.

I'll take a stroll in the parks and look at the flowers, and then backreturn home to sort out the videos and photos on my phone.

If you want to keep "parks" plural, "a stroll" should be plural as well (so "strolls"), unless you'll be visiting more than one park in one stroll.