Planning on participating in Samhain this year. I'm planning on smudging the house before and after my silent supper and before opening the house to guests, letting it be known I don't want negative unwanted guests.
Is there anything else I should consider incase things go wrong and I end up with a troublesome spirit at our supper or in our house?
I usually leave a candle in the window to welcome spirits, but I stand outside my door and state that all spirits who do not wish harm are welcome. So just state something like "I welcome all my departed loved ones home for the night. No other spirits are welcome in my home." Also, for your supper, set places for specific people. If your great uncle loved scotch, leave a glass of scotch at his seat. If your grandmother loved purple, place purple flowers and purple napkins at her seat. Any spirits who ignored your request would not have a seat at the table, and will typically leave.
I've always lived with spirits and I've always welcomed spirits into my home on Samhain and have never had a negative experience, so just take a deep breath and tell yourself you'll be fine. You might wish to wear a protective item to keep yourself safe during the time spirits are in your home, but sageing before and after as well as casting a protection spell afterwards you have nothing to worry about. Plus, as KTS mentioned, jack-o-lanturns are meant to scare away unsavoury spirits and entities.
I'd suggest layering your wards with your intention so that it is abundantly clear that you want no negative visitors. Besides that, you should also have some sort of simple banishing spell on hand in case anything major happens and it is needed. Otherwise, all of the suggestions above are great. I particularly agree with the wearing something protective idea.