River or ocean? Pick the cruise that's right for you

What's your cruising style: river or ocean?

As with many things, size matters. The biggest differentiator? Those massive, oceangoing ships packed with thousands of passengers are themselves the destination: floating cities with lots to do and see. Not so with river ships.

River ships, trim and nimble, are engineered to dock in the heart of your destination — a short walk from the Eiffel Tower in Paris, as an example, or steps from the French Quarter in New Orleans.

As Richard Marnell, senior vice president of marketing for Viking River Cruises, frames it: "River cruising harks back to what ocean cruising has gotten away from: the destination — being able to experience the destination in an authentic and intimate way."

When it comes to figuring out your personal cruising style, there are lots of moving parts. How do you feel about crowds? If you're like me, the crowds on the oceangoing ships can be off-putting, but they also offer a restful anonymity that you don't find on river ships, which typically accommodate fewer than 200 passengers.

What are your entertainment requirements? Large ships provide an abundance. You can pretty much do everything from clubbing to climbing. When I sailed on Celebrity Silhouette in the Caribbean in April, I almost needed a magnifying glass to make out the 100-plus entertainment listings in the daily newsletter. Among them, bocce, bingo, a makeover workshop, a social media lecture, and an LGBTQ & Friends social hour. The entertainment on most river ships consists of a solo piano player.

Here are four other categories to consider:

A lot of ocean cruisers are sticker-shocked when they research river cruises. Why? It's not difficult to find ocean fares that cost as little as a few hundred dollars. But remember that most ocean cruises adhere to a pay-as-you-go business model. I've had shipboard bar bills that cost more than my cruise fare. Shore excursions, alternative restaurant admission fees, cocktails — they all add up.

Most seven-night river cruises, in contrast, start at roughly $2,000 per person and can rise sharply from there. But almost everything typically falls under that fare umbrella, including most shore excursions, Wi-Fi, port charges, room service, all onboard meals, tips for local guides, bus drivers and luggage porters, and wine, beer and sodas with meals.

The bottom line: Do the math. Know before you go.

With all the activity, the large oceangoing ships can feel a little frenetic — and like you're being hit with the hard sell. Can I upgrade your drink? Can I interest you in a luxury watch? Heads up: The art auction starts at 3 o'clock!

Were it not for the vibration of the engine and the motion of the ocean, you wouldn't even know you were on a ship. That's why it's important to find a quiet spot on deck or on your own balcony where you can appreciate the rolling of the waves, the smell of the sea and the beauty of the horizon. Otherwise, unless you are on a massage table or in your cabin, tranquility can be hard to come by.

Back to crowds: At one point on our Caribbean cruise, five ships were in port at the same time — representing some 20,000 warm bodies. If fun in the sun is your driver, it's all to the good. But don't expect to experience, in any real way, a place or a culture that is crawling with tourists.

River cruises are about immersing yourself in a destination, whether it's diving into all things Lewis and Clark on the Columbia and Snake rivers in the Pacific Northwest or exploring Old World vineyards, cellars and wines on a Douro River cruise in northern Portugal, as I did on AmaWaterways' 106-passenger AmaVida a few weeks ago.

Entertainment is scant on river cruises, because the focus is on the opportunities that lie outside the ship: dinner and drinks at a riverfront cafe, a stroll through an ancient walled-in city, shopping for local wares.

River cruises generally include one shore excursion each day, often led by local guides. It's surprising how busy an itinerary can get. During a single day on the Douro cruise, we toured the city of Porto, which includes a UNESCO World Heritage Site; sampled port wines in an old cellar; did a scenic sail on the river; enjoyed a wine tasting and lecture presented by the ship's Napa Valley wine host; and topped it off with a pre-dinner wine and cheese tasting at an estate that dates back 300 years.

One of the best parts of a river cruise is watching the scenery unfold before you: terraced vineyards that look like an abstract painting, children playing on a riverbank, the sheer spectacle of passing through a lock. A scenic sail can be heart-stopping.

I've taken lots of photos on river cruises — on the Nile, the Danube, the Seine, the Mississippi and more — but what has really stayed with me is what I felt and learned there.

It's not just about how you wish to cruise, but with whom. There are lots of combinations: families, solo travelers, couples and intergenerational groups, to name a few.

It's fair to say that river cruises are designed to appeal to travelers who want a serene, adult-focused, destination-driven experience. Some lines don't even allow kids 13 and under.

River cruises do have a reputation for attracting an older demographic, which can sometimes frustrate younger guests on shore excursions who prefer to move at a faster pace. AmaWaterways solved this issue by dividing groups into "gentle" walkers, moderate walkers and active hikers. This worked great for me and my dad. He did the gentle walk, and I did the moderate or active ones, but we saw pretty much the same things.

As for ocean cruises, options abound to please any passenger mix. They do an especially nice job catering to young families with offerings that include supervised age-appropriate activities, athletics and, in some instances, child care.