Hi and welcome.

1/ Avoid maps which are really lower than 45 sec, I think that 42 sec minimum is a good limit.

2/ Avoid Island tracks. Really. Big jumps are prohibited in Tech, and every Island Tracks contain at least one (except IslandD4, which has loops).
3/ Desert tracks : you should go with DesertC5 and D3, because other C, and D1 and D5 are too short, D4 has a big annoying jump (and more globally, the map itself is annoying ^^) and D2 has random things.
4/ You can maybe take StadiumD2 and D4, because D2 is something like a bit tricky and D4 is a good tech track.
5/ About Rally : D4 and D5 pass well, as C5, so you can take all three.

6/ About Bay : D1 is something like f***, D2 has a cut and isn't that good, I think you can take D3, D4 has a big annoying jump and D5 has a cut. So D3 and D5.
7/ About Coast : D1, D2 and D4. D3 is annoying and has a big annoying drop, and D5 has a damn jump.
8/ Finally, avoid Snow. C4 is a s***, D2 isn't that bad maybe but there's a loop, and... Hm yes, just avoid Snow.
Finally, to recap :
DesertC5
DesertD3
StadiumD2
StadiumD4
RallyC5
RallyD4
RallyD5
BayD3
BayD5
CoastD1
CoastD2
CoastD4
So no Island and no Snow.

Good luck for your LAN
