2026 Keystone Montana3857BR

The 3857BR is the Montana built for families. Its defining feature is a middle bunkroom with a loft above it — a dedicated kids’ or guest sleeping zone amidships, separate from the private rear bedroom suite — which pushes the plan’s sleeping capacity to eight, the most of any profiled Montana. Four slides open the main living and kitchen area, keeping the family’s shared space generous even with the extra berths.

It does this without giving up the luxury build. The 3857BR carries the same 12-inch I-beam z-frame chassis, walkable Alpha TPO roof, Four-Season Living package, La-Z-Boy furniture package, hardwood cabinetry and 18-cubic-foot residential refrigerator on a 2,000-watt inverter as the couples’ plans, with a king bed in the rear suite, a 50-inch living-room TV and a single 15,000-BTU Coleman Mach heat-pump air conditioner standard. RVUSA lists a 3,050-pound dry pin — the heaviest of the six, reflecting the forward bunkroom mass — against the line’s 18,000-pound GVWR, which leaves a 2,382-pound payload.

At an MSRP of $130,688 it sits alongside the other large plans on price. The trade-off to read carefully is payload: at 2,382 pounds it is the tightest of the profiled plans, and a family’s gear, water and supplies eat into it quickly — weigh the loaded coach. For families who want Montana luxury and need to sleep eight, the bunkroom-and-loft 3857BR is the plan.

Montana is Keystone's flagship luxury fifth wheel and the best-selling luxury fifth wheel in North America. The line runs to fifteen floorplans for 2026; the six highest-demand layouts are profiled here in full, and the rest — along with the lighter, lower-profile Montana High Country sub-line — are catalogued on the line hub. The 3857BR on this page is highlighted; each other profiled plan links to its own page.

This floorplan carries its water comfortably. A full 70-gallon fresh tank is roughly 25% of the 2,382-pound cargo capacity, leaving the 3857BR with a usable gear budget even when you tow full.

The published dry pin weight of 3,050 pounds is 20% of this floorplan’s 15,618-pound dry weight. Fifth-wheel pin weight rides in the bed of the truck, so it comes off payload rather than off tow rating — and it rises with the trailer as you load it, not in proportion to what you put over the axles.

Nothing above changes the ceiling. Loaded to its 18,000-pound GVWR the 3857BR is towing 2,382 pounds more than its 15,618-pound dry figure, and that is the number your vehicle has to be rated for — not the brochure weight.

Tank balance is generous here: 70 gallons of fresh against 88 grey and 49 black, so waste capacity keeps pace with supply and the fresh tank is the constraint that ends a dry stay.

Ranked by GVWR, the 3857BR sits 10 of 13 in the Montana line: 18,000 pounds against a line that runs from 16,480 to 18,000 pounds. That position is the useful thing to know, because the plans immediately either side of it are the real alternatives.

Either side of it in the same line: Montana 3795FK matches it exactly at 18,000 lb GVWR; and Montana 3901RK matches it exactly at 18,000 lb GVWR.

7 other Montana plans share this floorplan’s 18,000 lb GVWR, so the ranking above separates plans that tow to the same ceiling. On a shared chassis the figure that actually differs between them is cargo capacity and where the weight sits, not the rating.

Against the 3857BR: the Cedar Creek 381MUD is 2 ft longer; the Influence 3003RL is 6 ft shorter and sleeps 4 fewer; the Paradigm 375RD sleeps 3 fewer. Those are differences in the published numbers only — what they cost, how they are built and how they live are separate questions each of those pages answers on its own terms.

Those are the nearest fifth wheels from other lines by weight — one per line, picked by proximity on that figure and nothing else. They are listed so the same tow vehicle can be checked against real alternatives, not because they are equivalent inside; layout, build and price diverge sharply across that group.

For scale, the Montana floorplans profiled here run 12,881 to 15,644 pounds dry and 35 to 43 feet of exterior length across 13 plans. Where a floorplan falls in that spread usually says more about which vehicle can tow it, and which site it fits, than the layout name does.

Every profiled floorplan in this line, with the full weight table, is on the Montana line hub.

This catalog tracks 18 specification fields per floorplan. Named sources publish 16 of them for the 3857BR. The rest are not shown, because the alternative is reading a figure across from a sibling floorplan or from what the segment usually does — and a number nobody published is worth less than an admitted gap.

Not published for this floorplan: tire specification, awning. If you find one of these in a manufacturer document for this plan, it belongs on this page.

The completeness figure at the foot of this page (98%) measures the same thing on the full field set: it is a measurement of how much this floorplan’s manufacturer publishes, not of how much research went into the page.

How every figure here was sourced and checked is set out on the methodology page.