2024 Forest River Sandpiper 391SAB vs 2025 Forest River Riverstone 39FKTH

Detailed Comparison

Choosing between the 2024 Forest River Sandpiper 391SAB and the 2025 Forest River Riverstone 39FKTH? Both are excellent options in the RV world, but they cater to different priorities.

Dimensionally, you're looking at 40.0 ft for the Forest River Sandpiper 391SAB and 42.5 ft for the Forest River Riverstone 39FKTH. The Forest River Sandpiper 391SAB carries an extra 1,300 lbs, which affects tow vehicle requirements and fuel economy.

For sleeping arrangements, the Forest River Sandpiper 391SAB offers room for 10 and the Forest River Riverstone 39FKTH can handle 5.

Looking at self-sufficiency, the Forest River Sandpiper 391SAB packs 66 gal of fresh water and 250W of solar. The Forest River Riverstone 39FKTH counters with 66 gal fresh water and 550W solar.

Price is often the deciding factor. The Forest River Riverstone 39FKTH starts at $55,000 MSRP, while the Forest River Sandpiper 391SAB commands $55,000 — a $0 gap.

Families with kids will appreciate the extra sleeping capacity and living space. Off-grid campers should pay close attention to solar wattage, battery capacity, and tank sizes. Full-timers should prioritize tank capacity, storage, and overall living comfort.

Remember, the perfect RV is the one you'll actually use. Pick the one that excites you most and hit the road.

When it comes to water management, tank capacity plays a major role in how long you can stay off the grid. Both units carry identical 66-gallon fresh water tanks, putting them on equal footing for dry camping duration. Gray water capacity favors the 2025 Forest River Riverstone 39FKTH at 79 gallons versus 43 gallons, which directly affects how often you need to find a dump station. The 2024 Forest River Sandpiper 391SAB also leads in black water capacity with 50 gallons compared to 40 gallons, an important consideration for families or full-time travelers.

Electrical systems are increasingly important as RVers rely on more electronics and appliances. With 550W of solar, the 2025 Forest River Riverstone 39FKTH outpaces the 2024 Forest River Sandpiper 391SAB's 250W setup, offering better energy independence away from hookups. Battery storage gives the edge to the 2024 Forest River Sandpiper 391SAB with 400Ah versus 350Ah, translating to longer run times for lights, fans, and charging devices overnight. The 2024 Forest River Sandpiper 391SAB's 2500W inverter can handle heavier loads than the 2000W inverter in the other unit, which matters if you plan to run a microwave, coffee maker, or hair dryer without shore power.

For solo travelers and couples who value maneuverability, the 2024 Forest River Sandpiper 391SAB with its more compact footprint will be easier to navigate through tight campgrounds and mountain passes. Families with children should lean toward the 2024 Forest River Sandpiper 391SAB, which sleeps up to 10 and provides more flexibility for overnight guests. Full-time RVers who spend extended periods off-grid will benefit most from the 2025 Forest River Riverstone 39FKTH's power setup and the 2024 Forest River Sandpiper 391SAB's water reserves, as these directly impact daily comfort and independence from hookups. Weekend warriors and seasonal campers who primarily stay at full-hookup campgrounds may find that the differences in tank sizes and power systems matter less, allowing them to focus on floor plan preference and overall comfort instead.

Both models carry the same $55,000 MSRP, so the buying decision comes down purely to features, floor plan preference, and brand loyalty rather than budget constraints. Since both models come from Forest River, buyers can expect consistent build quality, a shared dealer network, and comparable warranty coverage, which simplifies the after-purchase ownership experience.