The 391TB's case: 9 sleeping places and 327 gal of tanks
Sleeping capacity is the reason this plan exists: up to 9, 1 of 3 in the family, against 4 on each of the other two. The tanks scale with it. Gray and black capacities of 150 gal and 100 gal give a 327 gal total, 100 gal more than the 290RL or 300RK. Keystone's tagline sums the plan up as "Two Bedroom Suite w/ loft, Two Full Baths, Outdoor Kitchen".
The drawing, from the pin to the rear: a king bedroom with wardrobe, dresser, and washer and dryer prep; a full bath with shower and linen closet; the entry steps; a kitchen with range, microwave, and sink; and a living room with an XL sofa in the road-side slide, theater seating, and an entertainment center with fireplace and TV. The door-side slide runs alongside with a desk and pull-out dinette, a pantry, and a 16 cu ft 12-volt refrigerator. Past a step at the rear sits the second bedroom, with a king bed between flip-up nightstands, two wardrobes and a dresser, and a ladder up to a loft above it. Keystone's loft inset draws one bunk mat across the top and two running lengthwise beside each other, with two overhead cabinets and the ladder at one edge. The rear bath has its own shower, and an outdoor kitchen with refrigerator and TV is marked on the outside of that section.
Keystone's 2027 Montana High Country 391TB page and drawing →391TB checks: loft ladder, rear bath, outdoor kitchen, rear hitch
- Climb the ladder to the loft above the rear bedroom and lie on each of the three bunk mats. Measure them and the headroom before deciding who sleeps there.
- Walk the rear of the trailer. The drawing shows a second solid step outside the rear corner, by the rear bath, and a step between the living room and the rear bedroom; ask where the door served by that outside step opens and how the rear bath is reached from the loft and the bedroom.
- Open the outdoor kitchen on the door side with the 12 ft awning extended. Keystone lists it as standard with a refrigerator and TV, and it sits on the same end of the trailer as the loft and the second bath.
- Ask what the rear hitch is rated for. Keystone lists an accessory hitch on the 391TB where the 290RL and 300RK list a towing hitch, so do not assume this trailer can pull a boat or a second vehicle.
391TB in numbers against the 290RL and 300RK
The tradeoff sits in the last row. Two bedrooms, a loft, two baths, and an outdoor kitchen share 2,920 lb of cargo capacity, 1,060 lb less than the 290RL and 240 lb less than the 300RK, and every one of up to nine occupants brings gear. Keystone does list heavier-rated axle suspension on the 391TB than on the two shorter plans, but the published cargo figure is the one that limits what goes aboard.
Stepping down from the 391TB's loft and second bath
Both alternatives drop the second bedroom and bath and are listed for up to 4. Differences come from the published figures.
10 ft shorter, 3,590 lb lighter, and 530 lb lighter on the pin, with 1,060 lb more cargo capacity. A rear living room with theater seating and a center-island kitchen, and one bath.
Open record →Lightest pin in the familyMontana High Country 300RK9 ft shorter, 3,325 lb lighter, and 730 lb lighter on the pin at 2,055 lb, with 240 lb more cargo capacity. A rear kitchen with an L-shaped sofa, and one bath.
Open record →391TB published specifications
391TB: sources, dates, and the A/C height
Every figure here comes from Keystone's 2027 Montana High Country 391TB page, checked on 2026-08-21. The tagline, feature list, and 2027 drawing, including the inset labelled "Loft Area Above Bedroom", were read on 2026-09-26, when the specification table still matched these figures. Keystone marks the 391TB as a new floor plan. Every layout statement on this page, from the flip-up nightstands in the rear bedroom to the outdoor kitchen's refrigerator and TV, is read from that drawing and feature list.
Keystone labels the published exterior height, 13 ft 4 in, without separating the A/C, and the High Country list puts a bedroom air conditioner on the roof as standard alongside the main unit. The 160 in figure is 2 in under a 13 ft 6 in clearance; measure the unit.