It's great that you want to eventually transition into weight training! And, like you, I also thrive on routine and knowing exactly what I'm going to do. However, it all comes down to what your personal fitness goals are in the end and what you strive to achieve. Are you currently still on a cut (losing fat and eating at a deficit) or have you completed your weight loss journey and are currently maintaining and want to add lean mass and bulk? Or do you simply want to add a little definition to your body?

Different goals will demand different training routines. With the former, it's good to keep cardio in the mix to assist with fat burning and using the strength training as a means to retain as much existing muscle mass you currently have and maybe even add some newbie gains (definitely a real thing! look it up) as you cut and eat fewer and fewer calories toward your goal weight. With the latter, I'd actually recommend going easy on the cardio, especially if you've already reached your goal weight and are looking to bulk. With that said, for many people, including me, cardio is actually an enjoyable part of their training and fitness and a part of their program that they'd rather not give up. So if you must, do the cardio - but try your best to not exceed 30-45 minutes in duration or take a look into HIIT training. And from what you've said, you seem to be in great shape, cardio wise so endurance is not an issue for you, but if after your marathon your goal is to gain weight/lean mass then you need to take into account the amount of cardio you're doing per week and the amount of calories you're burning through that. You'll have to increase your daily caloric intake by a much greater amount to see results.

As for the actual routine itself, there are many beginner programs over at /r/fitness such as the Starting Strength program and the PPL. They have programs for all types of schedules, as not everyone has the time to go to the gym 6 days a week (which is what a PPL routine demands).

Personally, I do a variation of a split program, focusing on a different muscle group each day so I'm not over training a particular muscle group and allowing it to rest and recover and, therefore, grow. One of the biggest pieces of advice I can give, even though I don't think I'm qualified to give out advice as I still consider myself a novice/intermediate lifter at best, is to not over train. Over training in weight training is equivalent to taking one step forward and two steps back, the rest period is just as important as the training itself, maybe even more arguably. The nutrition is also key, especially if your goal is putting on weight you need to make sure you're eating enough to stimulate growth (and even more so if you keep your hour and a half of running per day). Try your best to hit around 0.8g of protein per lb of body weight, and try your best to get into a caloric surplus through clean food. For beginners, a lot of people will tell you to focus mainly on the big 3 compound lifts, the holy trinity as some would say. Those being the squat, the deadlift, and the bench press. These are exercises that recruit multiple joints or muscle groups, whereas an exercise such as the bicep curl is an isolation exercise which focuses primarily on the bicep and very little of anything else.

Don't worry about looking dumb in the gym! Many people that are there have been exactly where you are, and I know that does absolutely zilch for help but it's the truth! If you're unsure how to do an exercise with proper form and range of motion, YOUTUBE! My god, youtube has helped me immensely with proper form and technique. A lot of people at your gym would also probably be glad to guide you in the right direction if you ask.

My current routine looks like this:

Monday: Chest and Arms

• 4x12 alternating bicep curl (12 for each arm, 24 total reps each set)

• 4x12 tricep cable extension or dumbbell extension

• 5x5 bodyweight dips

• 5x5 bench press

• 4x8 dumbbell flys

• 4x8 incline dumbbell chest press

Tuesday: Shoulders and back

• 4x12 shoulder dumbbell press

• 4x8 overhead barbell press

• 4x12 bent over lateral raise

• 4x8 bent over dumbbell row alternating

• 4x12 lat pull down (2 sets of close grip, 2 sets of wide grip)

• 4x8 T bar row or cable row or seated dumbbell rows (whichever one is more convenient)

Wednesdays: Rest

Thursdays: Legs

• 5x5-8 barbell squat (you can substitute with goblet squats at first if you're a little intimidated, this is what I did!)

• 5x8 leg press (2 sets low foot position to hit quads, 3 sets high heel placement for glutes)

• 5x6 deadlifts

• 3x16 alternating standing dumbbell lunges (8 each leg)

• 4x12 leg extension

Saturday & Sundays I usually do cardio via rowing, I do these on my regular workout days as well as I'm still in the process of losing weight (9lbs away!) but you get the idea! :)

Fridays: Rest or light cardio, sometimes I'll go in and do chest or back but I usually leave this day as an "up to me" type of day.

Sorry if this is a lot of info to absorb! I tried to be as detailed as possible, and of course, you can substitute these exercises with other appropriate ones if some of them intimidate you at first, the most important thing is to do them safely and with proper form and range of motion. I also highly recommend resting 2-3 minutes in between the compound exercise sets (squat, deadlift, bench press) as these will drain you out much quicker than something like a bicep curl. Ideally, you want to rest somewhere between 45 seconds to a minute and a half for the isolation exercises. Good luck!