Lae plus inteéressante, chose 'est que nous pourrons aller [aux lieux ?] pendant lae petit-deéjeuner.

It would be simpler to just say "le plus intéressant", and it would also make the syntax lighter
Such a sentence is likely not to be understood for semantic reasons: going to which places?

[Nous donnerons sijuet de ujet ?] d'une heure et soixante minutes, puis, avec mes colleègues, nous allirons auà Notre-Dame et prenndrons [les gaâteaux de marche. ?]

I didn't understand the parts between brackets at all
If you intend this to happen in the future (I suppose it's the case since you've started with "pourrons"), you have to have future tenses here as well => donnerons, irons
"Notre-Dame" is a common noun, so it doesn't require articles, although a few people say "à LA Notre-Dame" where "la" stands for "la cathédrale"

C'este sera une bonne journéees.

Singular agreement => journée