B & H - thank you for alerting me to the maps that are available on the Lincs to the Past site.
On that 1906 map, look for the junction of Cowbridge Road and Spilsby Road, then look slightly left, and Bargate End is written diagonally.
It's called Wide Bargate on today's map, but old locals (who are very resistant to change!
) still call it Bargate End.
http://g.co/maps/f2v3qEnderby's and the Roadhouse Music Store buildings have been there forever.
That 1906 map is such a good find actually, especially as you can enlarge it in much greater detail than on some other sites.
Following Ruskie's find of San Francisco Terrace being on the south side of Spilsby Road you can clearly see it marked, and that there are only two other buildings on the south side until you come to Hospital (Bridge) Lane.
Drainside North simply
has to be what is marked on the 1906 map as Cowbridge Road. Too many other things fit for it not to be.
I did have to do a double-think in the 1911 census when I saw Pilley's Lane and Cowbridge pub itself mentioned on the same page, but then logic clicked in.
Schedules numbers for Drainside North start at 316 for the house and dairy, and end on that enumerators sheet at 333.
The next list (the one with Pilleys Lane and Cowbridge pub on) again lists Drianside North, schedule numbers beginning 334, with the uninhabited flour mill listed between 340 and 341, and ending on 357 with someone who lives in one of the Bede Houses at Hospital Bridge. The (pedestrian) bridge itself is exactly opposite Hospital (Bridge) Lane.
Those schedule numbers
prove that the walk must begin at the Spilsby Road junction and then go along to Hospital Lane.
FindMyPast have a census 'address search' and if you enter Skirbeck as the place, in 1881, you've got Drainside, and Drainside Willoughby Road amongst other entries, so it's obvious that it was called Drainside for many years, prior to it being Cowbridge Road for a few years. (Drainside is listed on the next page to Hospital Lane on the images.)
It could even be that the mapmakers made a mistake. Because regardless of what the map says, the road is listed as Drainside/Drainside North on official documents such as census returns (more than one!) and birth certificates.
Good thinking as to why that bit was called Drainside North, i.e. north of Bargate Bridge.
Ruskie - the drain south of Bargate Bridge isn't that long. A bit under a mile later (under the present day name of West Fen Catchment Drain) it enters the part of the river Witham known as the Haven.
http://g.co/maps/z9mdbTotally, off-topic, I didn't realise that the football ground was there as long ago as 1906.