Ketchum’s about to grow up. There are good things and bad about that, but there’s little doubt that when the community’s Planning and Zoning Commission and its City Council give final approval to the Sun Valley Company’s 138-acre River Run development and 110-foot hotel at the base of Bald Mountain — which they almost certainly will do in the next few weeks — Ketchum will have crossed a watershed.

On the other side lie America’s gaudiest and most commercial ski towns — Aspen, Park City and Lake Tahoe. Ketchum and adjacent Sun Valley could easily become one of them, full of Prada, Louis Vuitton and Dior boutiques and amusements and housing beyond the reach of real Idahoans.

Or Ketchum could keep its sense of perspective — and its unprepossessing ways — as Crested Butte, Steamboat Springs and Jackson have managed to do.

Of greatest concern is just how many of the 3,272 Ketchumites will be able to afford to stay that way.

In Jackson, working families can buy homes below resort-market value.

In Colorado, ski town developers must set aside up to 60 percent of their units for affordable housing.

Not in Idaho. Except for whatever affordable housing concessions local planners and elected officials can wheedle out of developers, folks of ordinary means are on their own in Blaine County. That’s why so many of them live in Shoshone, Richfield, Gooding, Jerome and Twin Falls.

Then, too, there are infrastructure concerns.

Ketchum has a street network that’s closer to Shoshone’s than Aspen’s and a transportation system that, despite the arrival of a mass transit system, still depends on cars andSUVs.

The good news is that the Sun Valley Company grew up with Ketchum, and knows its values and traditions. Among other improvements, it plans to create a 15-acre Big Wood River Ecological Park, including an area that currently boasts a large beaver pond.

And Sun Valley Director of Resort Development Wally Huffman’s idea — still speculative — to build a gondola from the resort to Ketchum and then to the base of Bald Mountain is intriguing. There’s no doubt that the hotel would be a first-class addition. Everything constructed by the Earl Holding company was been done exquisitely. And it would likely bring new dollars into an economy that’s been marginal even in good times.

But despite its resident glitterati and its seven-figure properties, Ketchum is still a small town, populated mostly by folks who actually have to get up and go to work every morning. That’s part of its charm. Will a high-rise hotel jeopardize that? That question should be thrown into the equation as the community weighs the pros and cons of the project.