To give you an idea ... my current base, have not killed the second boss yet but I 90% know what I'll have to deal with - also it can be upgraded later to stone etc.
https://steamcommunity.com/sharedfiles/filedetails/?id=2960968517
This is not that well-protected, I could build a small wall on the outer edges of the trench so that things would be kept busy and if they chose to attack directly, standing down there, probably would hit those before hitting the actual base-walls.
Ideally you would want to have the ground of your base a bit higher than everything outside to avoid archers doing harm. But from what you've told so far, you already did that.
But how exactly will the portal-entrance help you with archers? Because they were standing on the bridge and thus shooting directly at you main building? If you need further advice, maybe some screenshot would help.