01 What makes it unique
The 421FK is the cook’s plan. Its galley moves to the front of the coach, up in the raised section over the pin, where a full front kitchen with an island looks out under the front-cap windows, with six slide-outs opening the main level and a private rear bedroom with a king bed behind it. Dovetail drawers, a step-storage stair and the standard 18-cubic-foot French-door refrigerator carry the residential kitchen brief. It rides the full Riverstone build: a 102-inch-wide fully-welded frame, tandem 8,000-pound axles and an automatic six-point hydraulic level-up system.
Forest River lists a published 24,000-pound GVWR against the 18,786-pound dry weight, leaving a 5,214-pound payload and a 3,635-pound dry pin — the highest in the line. Its holding tanks are skewed to the galley with a 120-gallon grey tank, the largest in the line. Two 15,000-BTU heat-pump air conditioners, a Truma AquaGo tankless water heater, a Splendide stackable washer and dryer, a Fisher & Paykel dishwasher, 200-watt solar with a 2,000-watt inverter and a 65-inch living-room Samsung television are standard, under dual 16-foot awnings.
At a starting MSRP around $214,000, with US street pricing well below the placard, it is the front-kitchen Riverstone. For a couple who cooks and wants a bright front galley with an island, the line’s biggest grey tank and a private rear bedroom — and who tows with a one-ton truck rated for the highest pin in the line — the 421FK is the cook’s plan.
02 Full specifications
Dimensions
- Exterior length
- 44' 0"
- Exterior width
- 8' 6"
- Exterior height
- 13' 4"
- Interior height
- 8' 0"
Weights
- Dry / unit base weight (UVW)
- 18,786 lbs
- GVWR (max loaded)
- 24,000 lbs
- Net cargo / payload (CCC)
- 5,214 lbs
- Dry pin (hitch) weight
- 3,635 lbs
Capacities
- Fresh water
- 79 gal
- Grey water
- 120 gal
- Black water
- 40 gal
- Refrigerator
- 18 cu ft
Construction
- Frame
- Fully-welded frame · 102" widebody · riveted skirt metal
- Walls
- 3" hung-glass exterior walls · high-gloss gel coat · batten insulation
- Roof
- Fiberglass roof · 3/8" decking
- Underbelly
- 12V heated full docking station · 12V heated holding tanks
Running gear
- Axles
- 2 (8,000 lb tandem)
- Hitch
- Fifth-wheel (in-bed) · 2" bike-rack receiver
- Suspension
- LCI Road Armour™ · MORryde independent susp. optional
- Tires
- 17.5" H-rated on aluminum rims
Galley & bath
- Cooktop
- 4-burner gas oven · 30" convection microwave
- Refrigerator
- 18 cu ft
- A/C
- 30,000 BTU (dual 15K heat pump)
- Water heater
- Truma AquaGo Comfort · tankless on-demand
Sleeping & layout
- Sleeps
- 4
- Slides
- 6
- Entries
- 1
- Awnings
- 2 (16' & 16')
- Primary bed
- King
03 The Riverstone floorplan family
Riverstone is Forest River's top-luxury full-profile fifth wheel — a step above Cedar Creek and a cross-shop against the upper trims of Keystone's Montana and Grand Design's Solitude. The 2026 fifth-wheel line runs to seven floorplans, and all seven are profiled here in full. The 421FK on this page is highlighted; each other plan links to its own page.
| Floorplan | Nominal | Sleeps | Notable |
|---|---|---|---|
| 39RKFB | 42 ft | 4 | Rear kitchen, bath-and-a-half, lightest + shortest |
| 442MC | 44 ft | 6 | Mid-coach den, kitchen island, six slides |
| 421FK | 44 ft | 4 | Front kitchen + island, rear bed, biggest grey |
| 44DBL | 44 ft | 6 | Two full baths + murphy, dual entry, heaviest |
| 425FO | 45 ft | 6 | Front living, hidden front office, six slides |
| 420RE | 45 ft | 4 | Rear living + entertainment, biggest payload |
| 43BFC | 45 ft | 4 | Rear kitchen, bath-and-a-half, RV of the Year |
Riverstone is Forest River's top-luxury full-profile fifth wheel — a step above the Cedar Creek line and a cross-shop against the upper trims of Keystone's Montana and Grand Design's Solitude. The 2026 fifth-wheel line runs to seven floorplans, all profiled here. Every plan rides on a 102-inch-wide, fully-welded frame with tandem 8,000-pound axles, 17.5-inch H-rated tires, LCI Road Armour suspension, an automatic six-point hydraulic level-up system and a 12V heated full docking station, and ships with an 18-cubic-foot French-door refrigerator, two 15,000-BTU heat-pump air conditioners, a Truma AquaGo tankless water heater, a Splendide stackable washer and dryer, a Fisher & Paykel dishwasher, 200-watt solar with a 2,000-watt inverter and a 72-by-80-inch king bed as standard. Hitch weight, GVWR, UVW and CCC are published per plan on the Forest River factory pages, and each plan's UVW plus CCC equals its GVWR exactly. The published GVWR (up to 24,000 pounds) is rated by the full chassis, with the balance over the 8,000-pound tandem axles carried on the king pin; real loaded pin weights run higher — always weigh the loaded coach and confirm against your truck's payload and rear-axle ratings. An eighth Riverstone plan, the 42FSKG, is a toy hauler and is not catalogued here.
04 What owners & reviewers report
Front kitchen + island
A full front galley with an island under the front-cap windows — a bright, residential cook’s layout.
Biggest grey tank in the line
A 120-gallon grey tank — the largest in the line — scaled for a kitchen-forward plan and long stays.
Highest pin in the line
A 3,635-lb dry pin — the most of any plan — demands careful attention to the truck’s rear axle and payload.
Six slides, dual awnings
Six slide-outs and dual 16-foot awnings — the most open main level with shade on both sides.
05 How it compares
The front-living plan — a front lounge and a hidden office instead of a front kitchen.
The rear-kitchen plan — the lightest in the line, with the galley at the back instead.
Keystone’s front-kitchen plan — the direct full-size-luxury-FW cross-shop.