For anyone coming to this late, I found that there are firewall rules that are needed before the “–accept-routes” option works completely from LAN devices.
These are described in another forum post here: Tailscale cannot reach subnets on other devices - #27 by bswinnerton
Essentially, you need to go into LUCI interface (via System → Advanced Settings → CGI-BIN link) and then add a new firewall zone that allows traffic to the tailnet.
You can do this via Network → Firewall. Go to the Zones section and click the “Add” button, then change the following fields:
Name: tailscale
Input: accept
Output: accept
Forward: accept
Masquerading:
Covered networks: lan
Click the “Advanced Settings” Tab and then set:
Covered devices: Ethernet Adapter “tailscale0”
After Saving and then clicking the “Save & Apply” button, my LAN devices were able to access the subnets perfectly.