2026 Outdoors RV Back Country Series MTN TRX 20MKS

NewTravel trailer|Stock #31407|Located at Sumner RV Center in Sumner, WA
$66,339$86,218
Save $19,879

**Why We Chose This Back Country Series MTN TRX 20MKS **We selected this specific model because it represents the pinnacle of true off-grid freedom and rugged off-road capability for active couples. Built by Outdoors RV in the Pacific Northwest, the Back Country Series 20MKS is engineered specifically for remote primitive camping, national forests, and unpaved territory. The heart of its off-grid dominance is a built-in Cummins Onan 3.6kW LP generator, allowing you to run your entire electrical system anywhere wild trails take you. The clever floorplan maximizes interior space with a deep slide-out housing a residential sofa with built-in recliners, perfectly positioned across from a 32" swing-out TV. Up front, a space-saving premium queen wall bed flips up effortlessly into the wall to reveal a spacious daytime dining area. Complete with a fully equipped gourmet kitchen with solid-surface countertops, a full rear bathroom, and a 16' power awning, this mountain-ready coach is purpose-built for rugged exploration without sacrificing residential comfort.

Highlights of this Unit:

  • Built-In Onan 3.6kW Generator: True boondocking self-sufficiency with an on-board LP generator that powers your entire rig far away from RV parks.

  • Custom Off-Road HD Chassis: Built tough with a cambered off-road frame, rugged 16" Goodyear Endurance tires, and an HD fiberglass front cap to withstand backcountry trails.

  • Mountain Extreme 4-Season Design: Features advanced thermal pane windows and premium insulation barriers to keep you completely comfortable during freezing winters or scorching summers.

**The Sumner RV Difference **When you partner with Sumner RV, you are joining a 60-year legacy of integrity. As a family-run dealership hand-picked by the Nash family to carry on their tradition, we prioritize long-term customer relationships over transactional sales. To guarantee your absolute peace of mind, we invite new owners to spend their first night right here on our property along our year-round salmon creek—ensuring you are 100% comfortable with every feature before you head out to see Mt. Rainier.

Unit features & options

  • LG solid surface countertops
  • Single basin farm sink w/protective metal basin grid
  • High rise pull out faucet
  • Sunken range w/glass front
  • Glass top range, knife rack and granite design backsplash
  • Off grid 10 cu. ft. 12V refrigerator
  • Pot & pan drawer (most models)
  • Residential height countertops
  • Full extension 100 lb. metal drawer guides
  • Privacy blackout roll shades w/wall clips
  • Vaulted radius ceiling providing approx. 5" of additional headroom
  • Dual pane living room skylight w/shade
  • Ultra leather furniture & dinette sets
  • 12V triple charge station (charges iPad and cell phones)
  • Mountain dinette w/family XL table (most models)
  • XL dinette drawers
  • XL panoramic slide out windows (most models)
  • LED living room TV
  • Bluetooth sound system
  • Easy access home defense bed safe
  • Mountain comfort mattress
  • 12V USB ports by both sides of bed
  • XL bed nightstands
  • Plywood bed support w/bed storage

Full specifications

AC BTU13500 btu
Available BedsQueen Murphy
Awning Info17'
Axle Count2
Axle Weight5200 lbs
Black Water Capacity40 gals
Cooktop Burners3
Electrical Service30 amp
Ext Height11 ft 7 in
Fresh Water Capacity100 gals
Furnace BTU35000 btu
GVWR9995 lbs
Grey Water Capacity40 gals
Int Height6 ft 11 in
LP Tank Capacity40 lbs
Length25 ft 2 in
Number of Awnings1 ft
Number of LP Tanks2
Refrigerator Size10 cu ft
Refrigerator Type12
Shower TypeStandard
Sleeps2
Slides1
TV InfoLR Swing Out 32" LED
Tire SizeST235/80/16E
Water Heater Capacity10 gal

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2026 Back Country Series MTN TRX 20MKS

2026 Back Country Series MTN TRX 20MKS
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