Starring Helen Mirren. Rated PG

The Leisure Seeker is a worn-out Winnebago motorhome that hogs the lane and shudders at speeds over 50 mph. It speaks of another time—long before Xboxes and iPads—when gas was cheap and families spent their summers lazily crisscrossing the byways of America, stopping at campgrounds to read in lawn chairs.

The Leisure Seeker moves at the same lumbering pace as the 1975 vehicle that inspired its title. An aging couple skip town in their old RV, and head out on a road trip to Key West, without telling anyone, including their middle-aged children. This is panic-inducing to their kids because Ella (Helen Mirren) is suffering from a terminal illness, and John (Donald Sutherland) is showing strong enough signs of Alzheimer’s disease that he probably shouldn’t be driving.

Working from a script based on the novel by Michael Zadoorian, Italian director Paolo Virzì treats all of this with the kind of trite sentimentality one might direct toward the old camper—not the insight or complexity the subject, so well explored in films like Iris and Still Alice, demands these days.

This, despite valiant efforts from the two leads. The normally glamorous Mirren wears dowdy cardigans, oversized glasses, and orthopedic sandals, but allows Ella’s youthful, southern-belle charm to shine through. Sutherland ably transmits his retired professor’s flashes of childlike dependency, crankiness, and disorientation (“I want a burger!”, “We’re not home!”), before circling back to moments of clarity. It’s a testament to his authenticity that you’ll cringe while he bores complete strangers with minilectures on James Joyce and grammar.

Ella tries to jog his memory with slide shows on an old white blanket at the campsites, but after about the third such late-night display, the movie starts to feel as interminable as John’s impromptu minilectures. The most drama you get, until the last eighth of the movie, is a blown tire and the anxiety of watching John weave in and out of his highway lane. But it’s The Leisure Seeker that ultimately drives off-course, tonally, in its last act, with a far-fetched retirement-home storming and a resolution that takes a sharp left turn from sappy to bleak.

In the end, The Leisure Seeker can’t seem to help portraying seniors as cute people who do silly things. And that’s just the kind of patronizing attitude that Ella and John are trying to escape—even if it’s just in their beat-up Winnebago.