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Keystone Alpine 3700FL

Fifth wheelbuilt 2018–26Mixed build tierCommon on the used market
WHAT ONE COSTS
$88,400est. used (2026, 1 yr old)

Sticker was $122,746 in 2026. Out of production since 2026, so the used market is the only way to buy one. Estimate assumes a 2026 unit.

WHAT IT WEIGHS BEHIND YOUR TRUCK
~16,186 lbestimated as towed, for 2 people

dry weight 14,760 lb + fresh water (75 gal, full) 626 lb + propane + battery 200 lb + gear for 2 600 lb. Brochure dry weight omits water, propane, batteries and your gear; this estimate doesn't.

You want a tow rating around17,985 lb (10% margin)
GVWR (the sticker maximum)17,090 lb
Tongue weight, loaded~3,494 lb (22%)
Cargo capacity3,240 lb
WHICH TOW VEHICLES IT FITS: 18 OF 95

Judged the way the app judges: estimated loaded weight against each vehicle's rating less a 10% margin, per model year, because the 3700FL's published weights changed mid-run. Fifth wheels also need a pickup bed and are held to the fifth-wheel rating where published.

VEHICLETOW RATINGVERDICT
Chevrolet Silverado / GMC Sierra 2500HD (Duramax, max tow) '24-2622,500 lbfits, loaded, with 10% margin
Chevrolet Silverado / GMC Sierra 2500HD (Duramax) '20-2318,510 lbfits, loaded, with 10% margin
Chevrolet Silverado / GMC Sierra 2500HD (Duramax) '11-1918,100 lbfits, loaded, with 10% margin
Chevrolet Silverado / GMC Sierra 3500HD (Duramax DRW, gooseneck) '20-2636,000 lbfits, loaded, with 10% margin
Chevrolet Silverado / GMC Sierra 3500HD (Duramax DRW, gooseneck) '11-1923,300 lbfits, loaded, with 10% margin
Ford F-250 Super Duty (6.7 diesel, gooseneck) '20-2222,800 lbfits, loaded, with 10% margin
Ford F-250 Super Duty (6.7 diesel, tow pkg) '17-1918,000 lbfits, loaded, with 10% margin
Ford F-250 Super Duty (6.7 HO diesel, gooseneck) '23-2623,000 lbfits, loaded, with 10% margin
Ford F-350 Super Duty (6.7 diesel DRW, gooseneck) '17-1932,500 lbfits, loaded, with 10% margin
Ford F-350 Super Duty (6.7 diesel DRW, gooseneck) '20-2237,000 lbfits, loaded, with 10% margin
Ford F-350 Super Duty (6.7 diesel DRW, gooseneck) '11-1621,600 lbfits, loaded, with 10% margin
Ford F-350 Super Duty (6.7 HO diesel DRW, gooseneck) '23-2638,000 lbfits, loaded, with 10% margin
Ford F-450 Super Duty (6.7 HO diesel DRW, gooseneck) '23-2640,000 lbfits, loaded, with 10% margin
Ram 2500 (6.7 Cummins HO) '19-2620,000 lbfits, loaded, with 10% margin
Ram 2500 (6.7 Cummins) '11-1817,980 lb2018–19 model years fit
Ram 3500 (6.7 Cummins DRW, gooseneck) '13-1831,210 lbfits, loaded, with 10% margin
Ram 3500 (6.7 Cummins HO DRW, gooseneck) '25-2636,610 lbfits, loaded, with 10% margin
Ram 3500 (6.7 Cummins HO DRW, gooseneck) '19-2437,090 lbfits, loaded, with 10% margin
The 77it doesn't fit

These verdicts assume 2 people aboard with typical gear. See the margin for your truck and your crew →

THE SPECS
Length41.4 ft
Height (incl. A/C)13.3 ft
Width8.3 ft
GVWR17,090 lb
Dry weight14,760 lb
Dry tongue weight3,186 lb
Cargo capacity3,240 lb
Sleeps6
Slide-outs5
Axles2
Fresh water75 gal
Grey water78 gal
Black water78 gal
Air conditioning15,000 BTU
Awning14 ft

A missing row means the maker never published that figure: unknown, not zero.

WHERE PEOPLE SLEEP
  • 1× rear master king bed(Permanent)70×80
  • 2× tri-fold sofa and dinette in front living room(Convertible)—
HOW IT'S BUILT: 4/5
WallsLaminated fiberglass
FrameAluminum
RoofWalk-on
UnderbellyEnclosed

Keystone (Mixed tier): Keystone RV

YEAR BY YEAR: WHAT CHANGED
YEARSGVWRDRYMSRP
2018–1916,500 lb13,762 lb$122,746
2020–2617,090 lb14,760 lb$122,746
  • 2018Introduced
  • 2023Fresh water raised from 66 to 75 gal
  • 2026Final model year
FINDING ONE

Common: usually several for sale within a day’s drive. Why: Keystone is a volume manufacturer; 9-year production run. Estimated from build volume and production span, not a count of live listings.

OUR TAKE

The five-slide front-living Alpine that defined the line for most of a decade.

OTHER ALPINE FLOORPLANS
3011CK · 15,000 lb · sleeps 43020RE · 15,000 lb · sleeps 43100RE · 16,000 lb · sleeps 43102RL · 15,000 lb · sleeps 43120RS · 15,000 lb · sleeps 43220RL · 15,500 lb · sleeps 43303CK · 16,500 lb · sleeps 43320MK · 15,000 lb · sleeps 43400RS · 15,000 lb · sleeps 43450GK · 15,500 lb · sleeps 43450RL · 15,500 lb · sleeps 43500RE · 15,500 lb · sleeps 43500RL · 15,500 lb · sleeps 43640RL · 15,500 lb · sleeps 4the whole line →
Find one for sale

Live listings for the 3700FL on the big marketplaces. Each search opens pre-filled with this exact floorplan:

RV Trader ↗Camping World ↗FB Marketplace ↗Google ↗

Inventory varies by site and day. Slim pickings? search the whole Alpine line ↗

Is the 3700FL your #1, or just a spec sheet?

These are the facts. Whether it beats the other six thousand rigs for you depends on what you care about. Set your priorities as sliders, switch on your hard limits, and watch the whole market re-rank around them. Every exclusion explained, every margin shown.

See where it ranks for you →

Data compiled from manufacturer spec sheets, retrieved 2026-07.