Sandal face a play-off against Hinckley after surrendering a four-try lead at Sale to lose 31-22.
The final fixture pitted first against second with the victors claiming the title and promotion, and for long periods it appeared that Sandal would take the crown.
By half-time, they had scored three tries through centre Dave Martin, winger Simon Frewin and prop Rob Norbury and a conversion to lead 17-3.
They then scored the first try of the second half when winger Alex Orr extended the advantage to 22-3.
However, two tries and two penalties pulled the hosts back to within a point and when Sandal saw three men sent to the bin in a matter of minutes, Sale took advantage with a penalty and a converted try.
Morley ran in eight tries against rock-bottom Beverley to finish their campaign with a 52-12 win before dropping down to North One East. Seven different scorers crossed for the Maroons but the leading points-scorer was full-back Luke Stevenson, who had two tries and six conversions.
Huddersfield YMCA finished their first season in National Three North in eighth place following a 69-19 home win over Westoe. In perfect running rugby conditions, YMCA cut loose to score 11 tries, their highest win of the campaign, neatly bookending a season which began with a 29-24 defeat away to the same opposition.
Sheffield Tigers put in a far from vintage performance, but still managed to beat Burnage away from home, ending their season with a 40-24 win.
It took Tigers 25 minutes to get going properly but whenever they worked the ball out wide they offered a threat and scored the majority of their points in this way.
Full-back Peter Swatkins bagged a brace with other tries coming from prop Ed Simmons and wingers Liam Wallace and Henry Packard.
Mark Ireland also crashed over and Tom Outram converted all but one of the efforts. Tigers finish the season third in National Three North.
There was disappointment for Cleckheaton on the last day of the league season as they let a 24-7 lead slip in the last 20 minutes to lose 28-24 against a battling Firwood Waterloo.
Two converted tries from rolling mauls from Richard Piper and Rob Afoa Peterson were responded to as Waterloo wing Jacob Allen scored a solo try.
Ross Hayden’s penalty made it 17-7 at the break and he converted Martin Woodhead’s try after the interval.
Waterloo struck back. Allen went in for his second try and James Masters crossed from 30 metres out. Then in the last five minutes Reeve went over and added the conversion to seal victory.