Roswell sits in the eastern New Mexico plains, away from the main interstates. Almost everyone arrives by car.
By car: from Albuquerque, take I-40 east to Clines Corners then US-285 south — about 3 hours and 200 miles. From El Paso it's a 200-mile drive on US-285 north (about 3.5 hours). From Carlsbad Caverns it's just 75 miles north.
By air: the small Roswell Air Center (ROW) has a few daily American Airlines flights from Dallas/Fort Worth. Most visitors fly into Albuquerque or El Paso and drive.
By bus: Greyhound runs a couple of buses a day connecting Roswell with Albuquerque, El Paso, and Carlsbad. Slow and inconvenient.