Some suggestions ..
1) Don't use level 1 or 2 characters - too squishy
2) To keep options limited for new players don't go to too high a level ... level 7 is fourth level spells and you would lose someone new to the game ... too much to absorb. I would go with level 3 or 4 ... enough hit points to survive, archetype for flavour and a couple of abilities.
3) Use only PHB races and classes. Keep them simple, make the spell lists simple and ideally include a print out of the spells and special abilities with each character. Also include some particular character traits and/or habits in the character description ... it can go a long way toward roleplaying ... perhaps more than the usual bond/flaw/ideal set. However, the PHB has enough variety to make it interesting ... half-orc barbarian, half-elf paladin, human cleric, high elf wizard, halfling rogue for a classic if a bit cliche'd party.
As for the adventure ... the suggestion to include optional pieces is ideal. This lets you get the timing right for a 3 hour adventure. Try to design encounters with multiple ways out ... fight/flight/talk/sneak/bypass might all be good options depending on the scenario ... but keep in mind that if they talk or bypass a fight then it will take less time so you will want to have options later to lengthen it.
Finally, consider plot twists ... the theme is Escape so they might start imprisoned but maybe the entire encounter is a test or setup of some kind to see how the PCs perform. So although they are trying to escape ... maybe there are plot elements underneath that they aren't aware of ... done well, it can make the adventure more interesting especially when the players find out more about what is actually going on.
1) Don't use level 1 or 2 characters - too squishy
2) To keep options limited for new players don't go to too high a level ... level 7 is fourth level spells and you would lose someone new to the game ... too much to absorb. I would go with level 3 or 4 ... enough hit points to survive, archetype for flavour and a couple of abilities.
3) Use only PHB races and classes. Keep them simple, make the spell lists simple and ideally include a print out of the spells and special abilities with each character. Also include some particular character traits and/or habits in the character description ... it can go a long way toward roleplaying ... perhaps more than the usual bond/flaw/ideal set. However, the PHB has enough variety to make it interesting ... half-orc barbarian, half-elf paladin, human cleric, high elf wizard, halfling rogue for a classic if a bit cliche'd party.
As for the adventure ... the suggestion to include optional pieces is ideal. This lets you get the timing right for a 3 hour adventure. Try to design encounters with multiple ways out ... fight/flight/talk/sneak/bypass might all be good options depending on the scenario ... but keep in mind that if they talk or bypass a fight then it will take less time so you will want to have options later to lengthen it.
Finally, consider plot twists ... the theme is Escape so they might start imprisoned but maybe the entire encounter is a test or setup of some kind to see how the PCs perform. So although they are trying to escape ... maybe there are plot elements underneath that they aren't aware of ... done well, it can make the adventure more interesting especially when the players find out more about what is actually going on.
