In that case, let's try this...
SelectMission("m7");
SetMissionResetPlayerInCar("m7_wagon");
SetDynaLoadData("l1z6.p3d;l1r6.p3d;");
InitLevelPlayerVehicle("wagonA", "m7_wagon", "AI");
SetPedGroup(7);
SetForcedCar();
StreetRacePropsLoad("l1m7door.p3d;");
StreetRacePropsUnload("l1m7door.p3d:");
AddStage();
RESET_TO_HERE();
PutMFPlayerInCar();
SetMaxTraffic(2);
SetStageMessageIndex(18);
SetHUDIcon("mansion");
ShowStageComplete();
AddStageVehicle("smith_v", "m7_smithers_carstart", "race", "Missions\level01\M7race.con", "smithers");
SetStageAIRaceCatchupParams("smith_v", 80, 0.5, 1.0, 1.5);
AddStageVehicle("pickupA", "m7_lenny_carstart", "race", "Missions\level01\L1cop.con", "male2");
SetStageAIRaceCatchupParams("pickupA", 80, 0.5, 1.0, 1.5);
AddStageVehicle("sedanA", "m7_worker_carstart", "race", "Missions\level01\L1cop.con", "male2");
SetStageAIRaceCatchupParams("sedanA", 80, 0.5, 1.0, 1.5);
AddStageWaypoint( "m7_smithers_race1" );
AddStageWaypoint( "m7_smithers_nav1" );
AddStageWaypoint( "m7_smithers_race1b" );
AddStageWaypoint( "m7_smithers_race9" );
AddObjective("race", "both");
AddNPC("burns", "m7_burns_place");
AddCollectible("m7_smithers_race1");
AddCollectible("m7_smithers_race2");
AddCollectible("m7_smithers_race3");
AddCollectible("m7_smithers_race5");
AddCollectible("m7_smithers_race6");
AddCollectible("m7_smithers_race7");
AddCollectible("m7_smithers_race9");
CloseObjective();
AddCondition("position");
SetConditionPosition(1);
CloseCondition();
StageStartMusicEvent("m7_drama");
CloseStage();
AddStage();
AddStageVehicle("minivanA", "m5_sedan", "chase", "Missions\level06\sr3_1st.con", "male3");
SetMaxTraffic(2);
SetHUDIcon("bsedan_v");
SetStageMessageIndex(258);
SetStageTime(45);
AddObjective("losetail");
AddNPC("burns", "m7_burns_place");
SetObjTargetVehicle("minivanA");
SetObjDistance(200);
CloseObjective();
AddCondition( "outofvehicle" )
SetCondTime(10000);
CloseCondition();
AddCondition("damage");
SetCondMinHealth( 0.0 );
SetCondTargetVehicle("current");
CloseCondition();
AddCondition("timeout");
CloseCondition();
ShowStageComplete();
CloseStage();
AddStage();
SetHUDIcon("burns");
SetMaxTraffic(2);
SetStageMessageIndex(19);
AddObjective( "talkto" );
AddNPC("burns", "m7_burns_place");
AddObjectiveNPCWaypoint("burns", "m7_burns_walk_1");
SetTalkToTarget("burns");
CloseObjective();
SetCompletionDialog("there");
CloseStage();
AddStage("final");
AddObjective("dialog");
// INSERT MISSION DIALOGUE HERE!
CloseObjective();
CloseStage();
CloseMission();
...and this would be the load file:
LoadP3DFile("art\missions\level01\m7.p3d");
LoadDisposableCar("art\cars\smith_v.p3d", "smith_v", "AI");
LoadDisposableCar("art\cars\pickupA.p3d", "pickupA", "AI");
LoadDisposableCar("art\cars\sedanA.p3d", "sedanA", "AI");
LoadDisposableCar("art\cars\minivanA.p3d", "minivanA", "AI");
LoadDisposableCar("art\cars\wagonA.p3d", "wagonA", "OTHER");
LoadP3DFile("art\frontend\dynaload\images\msnicons\location\mansion.p3d");
LoadP3DFile("art\frontend\dynaload\images\msnicons\vehicle\bsedan_v.p3d");
LoadP3DFile("art\frontend\dynaload\images\msnicons\char\burns.p3d");
Make sure all the locations are mentioned in the m7.p3d file!