If a restaurant's parking lot is typically full, then the food inside is typically good.

That rule of thumb certainly applies at Maria's New Mexican Kitchen in Santa Fe, N.M. And while deciding what to eat can be tough — everything from green chile meatballs to tamales is offered — deciding what to drink is even tougher.

With more than 140 types of tequila and 200 margaritas, the drinks menu is staggering. The choices — with intriguing names such as Happy Camper, Moonglow and Platinum Crow — will have you feeling lightheaded well before the first round arrives.

"We started with 16 margaritas," said Al Lucero, who bought Maria's in 1985 because no restaurants were serving the tasty New Mexican food the Santa Fe native had enjoyed as a child. As he tried more and more food — and tequila — both his knowledge and the menu expanded. Lucero, author of "The Great Margarita Book," could easily be nicknamed Mr. Margarita.

Passport to tequila

Spaniards traveling El Camino Real brought tequila to Santa Fe more than 400 years ago. And while the margarita wasn't born in America's oldest state capital, it definitely matured here. Fittingly, the city launched the Santa Fe Margarita Trail (santafe.org/margaritatrail) last year where custom-created cocktails can be enjoyed along with a wealth of art galleries and museums.

Stop by the downtown visitor center to invest three bucks in the Margarita Trail Passport. In exchange for inclusion, the 31 featured bars and restaurants have developed special concoctions. Their recipes, plus a trail map, are included in the informative booklet. Holders get $1 off each of the listed margaritas and earn stamps good for free gifts with each purchase.

Start sipping at the La Fonda on the Plaza hotel, the only place providing stamps at three venues: La Plazuela restaurant plus two bars.

In warm weather, locals enjoy after-work cocktails at La Fonda's Bell Tower Bar, a rooftop gathering spot overlooking the city. Its new offering, the Bell Ringer, comes with a kick; it's made with Tanteo jalapeño tequila, Cointreau, jalapeño juice and lemon-lime juice.

It's no wonder that city fathers are encouraging responsible drinking by limiting the number of stamps to two a day.

Just off the lobby, La Fiesta Lounge serves a new margarita as well as a tequila flight containing four types of Herradura tequila.

Server Andrew Alas first offers the Silver, aged for 40 days.

"It has a soft taste," he explained. "It's really, truly light."

Under Alas' tutelage, guests then try varieties of reposado and añejo before he proffers a small glass of double-barrel tequila. It comes from individually numbered bottles bearing the hotel's name.

"It's aged for 11 months to give it a different taste," he said.

The liquor is smooth as silk on both the tongue and the back of the throat.

"We're now on our third barrel, so it's been really successful," said Shawn Murphy, La Fonda's food and beverage director.

"People associate tequila with margaritas. I don't drink it that way. I sip tequila," he added. "The tequilas they come out with now are as good as any brandy or cognac. They're just as smooth. It's amazing."

Packing a spicy punch

Peppers are a big deal in New Mexico. The village of Hatch, in the southern part of the state, is famous for its green chiles. No wonder another locals' favorite, Del Charro Saloon at Inn of the Governors, puts an emphasis on super-spicy ingredients in both its food and drink.

Del Charro's new special, the Santa Fe Trail margarita, will knock the socks off a timid out-of-towner. In addition to green chile-infused tequila, bartenders add green chile powder and red chile flakes. With that much spice, the Cointreau, lemon and lime juices almost seem like afterthoughts.

If that's not enough to make a gringo's eyes water, there are always the quesadillas topped with New Mexico green chile.

Fit for a cowgirl

Tourists who forgot to pack their antacid pills can always opt for the Cowgirl Cadillac margarita at Cowgirl, an indoor-outdoor rib joint near Santa Fe's up-and-coming Rail­yard District.

The restaurant's special is a gentle spin on the classic margarita. It's made from organic blue agave tequila, Grand Marnier, and sweet and sour mix, as well as fresh squeezed lime and orange juice.

"This conjures up, in my mind, this sexy cowgirl lounging in her Cadillac Eldorado with the big steer horns up front and her boots up on the dashboard," Cowgirl co-owner Nicholas Ballas said. The creation, he added (only partly tongue-in-cheek), is the result of more than 30 years of trial and error.

"It was night after night after arduous night of researching margaritas in Santa Fe," he said. "I finally found out how to make a good margarita."

Good enough for Redford

About a mile away at Maria's, where the passport drink is named for former owner Lucero, don't be surprised to find Robert Redford sitting nearby. A Santa Fe homeowner, the legendary actor has been dining here since he filmed "The Milagro Beanfield War" in nearby Truchas in the late 1980s.

Redford praised Maria's in his foreword to Lucero's book. "Is it fancy? No. Is it chic? No. Is the food good? Yes. But the margaritas — they are the best," he wrote.

Just try to avoid asking for a frozen margarita. That will make the bartenders wince.

"When you're doing a frozen margarita," Lucero pointed out, "you're getting a slushie, and it's mostly ice."