I've visited every US national park alone. Here are 8 mistakes I see first-time travelers make.

Reservations and timed-entry permits are the new normal for several of the most-visited US national parks.

However, because it's still a relatively new system, I often see travelers turned away at the gates because they're unaware they need a reservation.

Although there are occasionally workarounds when a traveler can enter those parks without a reservation, navigating them is frustrating and often leaves people looking for backup options instead of the trip they envisioned.

It's crucial to research the entry requirements long before your visit, especially in the busy summer months.

Many people think of freedom and spontaneity when considering a trip to the national parks. Although that can undoubtedly be part of the experience, travelers shouldn't wait until the last minute to secure lodging or campgrounds.

The booming popularity of national parks has caused a shortage of lodging and full campgrounds (many of which also require reservations in advance).

Making reservations early is the best way to save yourself any hassle (and likely some money on last-minute accommodations).

Although some national parks have cell service and WiFi, you should never count on either being available.

I always encounter travelers at visitor centers and shops in the parks begging for a WiFi password that they cannot access or does not exist.

It's essential to download offline navigation before entering a park, as there's no guarantee you'll be able to otherwise.

First-time visitors at a national park don't usually participate in overly technical or strenuous hikes. However, I recommend bringing a few items to stay safe.

I often see visitors hiking in flip-flops or heels without any water or supplies. Even on a relatively short hike, anything could happen.

I always pack the essentials — navigation, sun protection, a headlamp, a first-aid kit, a knife, fire, shelter, extra food, water, and clothes.

If you're on social media, you've likely seen viral photos and videos of bad behavior in the parks.

Unfortunately, this behavior seems to be escalating with increasingly bold visitors. In nearly every circumstance in a park, visitors should stay on posted trails.

Travelers should also become familiar with the seven principles of Leave No Trace, which provide guidelines for visiting the parks in a respectful manner.

It's shocking how close some national-park visitors will get to dangerous wildlife like bears and moose for a selfie or a thrill.

The rule of thumb is always to stay at least 25 yards from wildlife and 100 yards from predators.

I always recommend entering a national park as early as possible for several reasons.

Arriving early helps mitigate crowds, as there will likely be fewer people around earlier in the day. The morning hours are also the most tolerable for spending time outside, especially when traveling in the summer.

Every year, visitors encounter health emergencies and even death by hiking in the afternoon hours of a hot day.

The biggest mistake I see visitors make is pushing themselves beyond their physical limits.

For example, if a visitor is not acclimated to higher altitudes, a hike that seems easy or moderate on paper can become extraordinarily strenuous and even dangerous.

Knowing and respecting your physical limits is important when venturing into the parks.