I packed for a weeklong trip that involved a plane, train, and car. Here are 4 things I'm glad I had and 3 items I regret not bringing.

From fine dining restaurants to hikes in Arches National Park, I planned a vast itinerary for my six-day trip to Utah.

It all started aboard the luxury Rocky Mountaineer, a two-day train ride from Denver, Colorado, to Moab, Utah. After I arrived in Utah, I'd rent a car and explore the state solo for five days before hopping on a flight back home to Denver.

Everything I'd need for the trip would have to fit in my carry-on suitcase and backpack. My past trips on long-haul flights and cruises helped me prepare, but I wasn't exactly sure what I'd need for a trip that involved three very different modes of transportation: a train ride, a road trip, and a flight.

I came home from the trip with a suitcase full of dirty clothes and a better sense of how to pack for different modes of transportation such as planes, solo road trips, and train rides.

Here's what I'm glad I brought and what I regretted not packing.

After riding a train, flying in a plane, and driving a car, I plan to never leave for a trip without a reusable water bottle.

While I had unlimited access to water on the Rocky Mountaineer, it was nice not to pester anyone for refills as my bottle kept me hydrated for long periods of time.

On the road-trip portion of my Utah trip, I was thankful I had a 34-ounce water bottle that allowed me to skip gas-station stops when I got thirsty. On the plane, I was happy I could pass on the plastic cup and drink from my Nalgene instead.

Ultimately, packing a water bottle saved me time and money, plus it was a small way I created less pollution while I traveled.

There were moments during the plane, train, and car rides where I was thankful I had either music, a book, or something to fill the time.

The Rocky Mountaineer differentiates itself from other train companies and advertises itself as a vacation in and of itself. Each train car has curved, glass-dome windows, which I thought helped maximize the views of the landscapes I was passing by. Onboard, a train host functions as a tour guide, who share tidbits about the region's history and landmarks along the route.

But when the train host wasn't diving into a story, passengers were left to their own devices. As the hours stretched on, I was glad I had my phone with a pre-downloaded book.

Meanwhile, long drives on open roads required upbeat music to stay focused, and a short flight home to Denver went smoother with my downloaded podcasts and TV shows.

A jacket is almost always on my packing list. I tend to run cold, and this was the case for both the plane and the train portions of my trip.

The AC was blasting as we barreled across the West on the Rocky Mountaineer, which meant I wore my corduroy jacket for the 15-hour ride. The same was true for my flight back home to Denver.

Meanwhile, on my road trip, I was behind the driver's seat and in control of the temperature. It was the first and only time that my jacket wasn't all that useful, and a major perk of a car ride. But I was ultimately still glad I packed it for a road trip as it came in handy for stops at cold restaurants and when the temperature plummeted each night.

As I've previously written, I don't travel without chocolate. At some point on every trip I've ever taken, I've craved something sweet. So I always pack a few chocolate bars.

There were multiple times in the plane, train, and car when I was thrilled I had a Trader Joe's chocolate bar in my suitcase. For instance, as I was driving along the highway, caffeine jitters from guzzling two sodas started to kick in. I was in the middle of nowhere and luckily had a bar of chocolate to hold me over until I could grab a real meal.

On the train, there was a constant flow of food, yet I still found myself itching for something sweet. Fortunately, I had my own chocolate.

No matter the mode of transportation, I'll likely get peckish, so I'm glad I had chocolate at hand.

Whether it was sitting on the train, lounging in my airplane seat, or reclining in the driver's seat, there were times when I wanted a salty snack.

Before hopping on the Rocky Mountaineer, getting behind the wheel of my car, or boarding my plane, I should've made a quick stop to grab a bag of Goldfish or popcorn to keep me satisfied throughout my six-day Utah trip.

For the plane, train, and road trip, having a backpack meant all my necessities were within arm's reach.

For the Rocky Mountaineer train ride, I dropped off my suitcase the morning I boarded the train, and I wasn't reunited with my bag until I reached my hotel that night.

This meant I couldn't access anything in my suitcase for the majority of the day, so I packed the belongings I'd wanted for the ride in my backpack.

I had a similar experience on the plane. While my carry-on was stationed in the overhead bin for my flight home, it was inconvenient to dig around the bag once I boarded the plane.

And for pit stops along Utah's highways, I was glad I could hop out of the car with a smaller bag instead of lugging around my carry-on suitcase or juggling my phone, keys, water bottle, and wallet in my hand.

While the glass-dome windows were one of the biggest perks of the Rocky Mountaineer train ride, it was also bright throughout much of the ride.

Unfortunately, I only had a cheap pair of sunglasses to help reduce the glare. I ran into the same issue as I drove across Utah exploring Arches National Park, ghost towns outside of Salt Lake City, and a town dubbed the state's "Little Switzerland."

For future trips, I'm making sure I invest in polarized lenses.

While I researched where I was going and what I was doing in Utah, I would've loved to fill empty time digging into Utah instead of scrolling on my phone.

This was especially true on the Rocky Mountaineer. I hadn't considered packing things that would have enhanced my learning experience during the train ride. For instance, I would have loved to have a local guide on the flora and fauna of the region or a book on Utah's national parks.

Similarly, a guide book could have helped me discover hidden gem pit stops on my road trip.

For future trips, I'll find a small guide to include in my carry-on.

For future trips, I'll continue packing a day bag and water bottles, and I'll make sure a pair of polarized sunglasses is always on my list.