Some rules references that may help you find uses for them:
RB5 Hidden-Mines/Entrenchments (including A-T Ditches; B27.56, O11.621) may be placed in a paved-road hex that also contains shellholes; mines set up thusly can attack regardless of whether or not the unit entering their Location is using the road rate/bonus. A roadblock may also be set up IN a gully or Culvert to block a gully/Culvert hexside. A roadblock IN a gully or Culvert may be crossed by Infantry only via a Minimum Move, does not affect Bypass in adjacent Level 1 Locations, and for LOS purposes is treated as a wall at Level 0 (the level of a unit IN a gully on the RB map).
RB6 Trenches (including A-T Ditches) are considered to "connect" (as per B30.8) to (but not through) all ADJACENT building/rubble Locations [EXC: not to a Location that is rubbled during play of that scenario] (see also O6.21; and O6.6, last sentence). Infantry entering such a building/rubble Location need not pay an extra MF to leave the trench in that Location, but must still pay applicable building/rubble COT. Infantry leaving such a building/rubble Location need not pay an extra MF to enter a "connecting" trench; Infantry may not enter such a trench while using Bypass Movement; nor may they use Bypass MOvement while in such a trench; nor may they exit such a trench to directly use Bypass Movement. A unit entering/leaving a building/rubble Location via a "connecting" trench is not subject to Snap Shots as it does so. A vehicle must pay the appropriate MP-costs/penalty to cross such a trench while using VBM; hence those vehicle types not allowed to cross a trench may not do so while using VBM. Infantry may enter a Fortified Building Location as if that Location were not Fortified provided they enter it from a trench/AT-Ditch that is "connected" to that building Location.
O6. RB Cellars
6.1 All multi-hex, non-Factory buildings depicted on the RB map contain beneath their ground-level Location (i.e., at building level -1) a RB Cellar level (beneath which is that hex's sewer level, if any).6 A RB Cellar Location is considered the equivalent of another non-rooftop building Location in that hex (even for falling rubble [B24.12] and Victory Condition purposes) except as specified otherwise. The RB Cellar level is ignored when determining the Base Level of a building hex.
6.11 FORTIFIED: A RB Cellar Location is always considered to be a Fortified Building Location with a TEM of +4 [EXC: +3 if wooden]. All Fortified Building rules apply except as stated otherwise. A RB Cellar Location can be Breached (B23.9221) only across a hexside that is common to an ADJACENT RB Cellar Location.
6.2 ENTRY: Only Infantry/SW may set-up-in/enter a RB Cellar, and their presence therein is indicated by placing them beneath a Cellar counter. Infantry may enter/exit the RB Cellar level only via a Stairwell, Manhole, or a "connecting" Trench or Tunnel, and only as per B23.922 [EXC: see O.2A and SSR RB6]. Infantry already in a RB Cellar may directly enter an adjacent RB Cellar Location only if the two hexes involved share a building hexside, as determined by the building's depiction [EXC: if Rowhouse].
6.21 All Trench "connections" (SSR RB6), Manholes, and Tunnel entrances/exits "open into" the RB Cellar level if it exists in that hex [EXC: if the ground level above the RB Cellar has been Rubbled; 6.6]; otherwise, Sewer/Tunnel (B8.) and Trench (B27.5) rules are unchanged [EXC: a tunnel's entrance and exit Locations may be at different levels].
From the
RB SSR and rule book pages O5 & O6. Take a careful look at the examples for the RB Cellar rules there, also.
, I *think* I have already implemented some of your suggestions JR so will check later. Thanks everyone for confirming my general suspicions though 