CBS, staring down the barrel of 22 new shows on NBC and ABC next fall, is expected to stand relatively pat with its lineup, based on the assumption that providing viewers some stability and familiarity may be the best course.Last fall, the four prime time services debuted 33 new shows, making it tough to get viewers to sample new series. As a result, the season yielded few hits, and its top new series was “Dr. Quinn, Medicine Woman,” which bowed in January. A priority for top-rated CBS will be solidifying “Dr. Quinn’s” lead-in Saturday and putting that night in the web’s win column. With NBC offering comedies and ABC a variety show at 9 p.m., CBS will likely look for an hour series (Fred Silverman and Dean Hargrove’s Dick Van Dyke hour, which has an eight-episode order, has been mentioned) to bridge the gap between “Dr. Quinn” and the Chuck Norris action series “Walker, Texas Ranger.” Also, CBS is said to be considering another stab at comedy from 8-9 p.m. Wednesdays leading into “In the Heat of the Night” and “48 Hours.” Despite fairly good results for reality series “How’d They Do That?,” sources say CBS believes it can sell sitcoms for more to advertisers in the upfront market and has the Lorimar show to fall back on. The web tried a similar approach two seasons ago with “The Royal Family,” which performed reasonably well at 8 p.m. Wednesdays prior to the sudden death of star Redd Foxx. ABC will also have two unproven comedies in the hour, “Thea” and “Joe’s Life.” Some of CBS’ toughest choices involve configuring its Monday and Friday comedy blocks, with “Designing Women” gone and “Major Dad” on the fence. TriStar’s “Good Advice” is among the first-year shows expected to come back, with Shukovsky English Entertainment’s “Love and War” likely to hang on to the post-”Murphy Brown” slot and the Thomasons’ “Hearts Afire” possibly shifting to Friday. New comedies given the best chance for making the lineup are “Dave’s World,” an in-house show based on work by columnist Dave Barry and starring Harry Anderson; and “It Had to Be You,” a Lorimar sitcom pairing Faye Dunaway and Robert Urich. Others mentioned include “The Nanny,” the latest Fran Drescher sitcom, from TriStar, possibly for midseason; and “Tall Hopes,” Warner Bros.’ pilot featuring stand-up comic George Wallace. With “Cheers” and “Knots Landing” gone, one big question mark for CBS is how to attack Thursday. The net is expected to unveil its fall lineup by the end of this week and will present it to advertisers Monday.