Looking for some advice, hopefully the IL HTF can chime in rather than the usual GD response of go around the state! I'm moving cross country and one of our hotel stops is just east of STL in Fairview Heights, IL... I will be travelling with a trailer containing my firearms, unless they get lost in a boating accident prior. They will be stored in a locked trailer, and in a separate locked steel chest. Ammo and magazines will be locked up separately. I know FOPA doesn't apply to a overnight stay, is there anything else that I need to do in the state of IL to be legal here??

Transporting....unloaded, enclosed in a case, or inaccessible...so your guns in the trailer are good to go if they are unloaded.
You can have inside your vehicle (transport) unloaded and enclosed in a case...your glove compartment or console with a lid will work...Ammo can be anywhere in vesicle  as long as not in the gun.
If you are legal to carry in your home state, you can have loaded inside your vehicle...must be unloaded and enclosed to leave the vehicle.  Once in your room, you are legal to have loaded as it becomes your abode.

Not familiar with Fairview Heights, but darn that is a little too close for comfort to East St. Louis (crime ridden hellhole) for my liking!

IL isn't terribly friendly to NFA stuff, but otherwise you should be good.  No statewide AWB or mag caps, just a few municipalities.

I live in Swansea, just south of Fairview Heights (city limits are borders of each other).

There's a Hampton Inn in Fairview, right off the exit, that is clean.  I would, however, recommend you looking at staying a bit further East.

There's a Best Western in Mascoutah, IL, at the intersection of Hwy 4 and I-64.  That is going to get you far enough East that worrying about trailer theft should not be an issue.

This or stay in O'fallon at the Drury. The police dept has a car in that area all the time. Not due to crime but keeping the area nice.

Thanks for all of the info... To be honest, there is so much going on that I didn't even think about the East STL aspect.

I may go ahead and push into STL and stay somewhere near the airport area. Our problem is that we will be travelling with 3 large dogs so I have to find nice enough hotels that allow our 3 fur kids.

I would avoid the airport area. Get out of the metro on the Stl side. If I remember right Drury hotels are pet friendly.

Fairview Heights is not "East St Louis" and is way safer than the airport area IMO. Airport is right next to a place called Ferguson that you might have heard of. Stop in Effingham IL (presume you're driving on 70) if you want to completely avoid the metro area, or else push on through to St Charles MO or beyond.

As far as the firearms, as previously stated IL transport laws are less stringent than FOPA so no worries there. No state AW or magazine bans, and no local bans anywhere close to what I presume is your route. Concealed carry of a loaded handgun (no long guns) is ok IN VEHICLE ONLY, as long as you have carry in your home state (preferably with a resident carry permit).  Loaded firearms must stay in the vehicle, or else be unloaded if exiting the vehicle. You can also have a loaded firearm in your hotel room as that is your domicile, however temporary.