I particularly enjoy the routes that have more than two end points, even if it's just a branch, like LIRR, Riesa - Dresden, West Cornwall, Brighton Mainline. It always adds something more than pure mileage. Some examples could be: Koeln - Duesseldorf - Duisburg - Oberhausen with branches to Bergisch Gladbach and Duesseldorf Flughafen Terminal Freiburg - Basel with branches to Zell Berlin - Halle with branches to Halle-Trotha and Halle-Nietleben Munich - Rosenheim (Salzburg/Kufstein) with the Ebersberg branch Munich - Garmisch with branches to Kochel or Oberammergau Koeln - Koblenz (east bank) with the airport loop and Siegburg/Bonn Stuttgart - Ulm with the Kirchheim/Teck branch Crewe and Stoke to Manchester including the Airport/Styal line Manchester Victoria and Piccadilly to Blackpool North and South Airdrie to Helensburgh and Balloch (via Yoker or via Westerton) Motherwell and Larkhall to Dalmuir and Milngavie (via Hamilton and Newton and Yoker or via Westerton) The C2C network Marylebone to Aylesbury via Amersham or Princes Risborough Rugby to Stafford via Birmingham and the TVL (or via Birmingham with the Walsall/Perry Barr lines) Victoria/Blackfriars to Croydon and the lines that criss-cross Smethwick Galton Bridge to Leamington/Warwick via Snow Hill Bern to Interlaken and Brig Basel to Zurich (direct or via Brugg) Zurich to Luzern, Luzern to Arth-Goldau, Arth Goldau to Zurich The Three Country Corner route (Lindau, Buchs, St. Anton) Brussels to Antwerp incl. the airport loop Amsterdam to Den Haag HS and CS via Haarlem or Schiphol with the Zandvoort branch Amersfoort to Bad Bentheim and Hengelo
I think a mixture of both is best. DRA and DCZ are great examples of that: DRA has a lot of branch lines (Großenhain, Meißen and the two parallel lines) and DCZ is quite straight forward with no branch lines. Both are two of the most well-received DLC from Germany and both variants have their upsides: A DRA-type route offers great variety of services each offering something different so you get the most value (in terms of play time) out of your money, but something like DCZ offers longer distance services where 1 service takes you 80km far and more than an hour of driving time.
How about this route Bochum-Dortmund/Hagen first end point is Dortmund Hbf it's where HRR meets the Wuppertal Dortmund Hagen via Witten Hbf & Hagen Vorhalle Rbf railway line S5 AI on RRO. 2nd end point is Hagen Hbf via Witten Hbf and Bochum Langendreer Junction. Freight trains run Bochum Ehrenfeld to Hagen Vorhalle for Wuppertal Steinbeck and Finnentrop by splitting it there. ÖBB Westbahn Salzburg Wien Hbf has different ends Freight trains run between Salzburg Gnigl to Wien Kledering others can use Verschiebebahnhof Linz and Wels.
