[This turned out to be quite long question, but I couldn't find anyone discussing my particular situation - long, training-like ride followed by a workday as a developer. It seems that all considerations are intertwined.]
A bit of current situation:
My company is moving (in 1-1.5 months) to new offices that will have shower facilities and that made me consider cycling to work.
I'm 189cm (6'2") high weighing ~120kg (265lbs).
10 years ago, I commuted 12km (7.5mi) for a short-term work, at the time weighing ~105kg (230lbs). Started with a 47 minute ride and got down to 18 minutes after 3 weeks (average speed of 40kph or ~25mph). That was on a 70's-era steel road bike with shifters on down tube (don't recall the maker).
The primary goal is to get in shape, while enjoying monetary savings in fuel costs and possibly a shorter commute (time-wise, more on that later).
The ride will be about 30km between two cities. It will consist of 6km/3.7mi fast (3 lanes) city road (60kph/37mph allowed, 80-90kph/50-55mph actual speeds); followed by ~20km/12.5mi of highway with shoulders and high congestion, avg. speeds of 25kph/15.5mph most of the span; ending in 4km/2.5mi of "slow" city traffic.
Elevation is negligible.
Weather is mostly hot, with temperatures in the 30-40C/85-105F range with 90+ percent humidity for about 6 months of the year, and about 25-30 rainy days. I won't cycle in rain/extremely windy weather.
The first consideration:
I know it will take several months of training before I can make that ride, and I'm planning to light up as a Christmas tree for safety/visibility. Considering that, do you think that this plan is insane and I should drop the whole idea? Can you elaborate as to why?
Regarding bike setup (from my research and budget):
[I know my weight is usually on the top or over-the-top of the range for most appliances (e.g. Segway and most electric bikes are rated to 115kg max.). I haven't seen any restriction for rider weight in specs, but that maybe because there are not a lot of people with that weight buying this level of bikes?]
Bike: I'm inclined towards
Felt Z95 mainly because all reviews praise its comfort for long rides and its rigidity. Now, I'm not sure what constitutes a "long" ride - maybe the reviewers are talking about 100km/60mi rides and for my intended purposes another bike will be more suitable?
Pedals: I'm thinking of Shimano's 105 (PD-5700, steel not carbon) with SH-11 cleats due to praises of durability from reviews. The wider plate should be better for me considering my weight. Am I right about these? Should I consider something else? Better? Can I get by with something cheaper (i.e. PD-R540)? Is 6 degrees of float is enough for such long rides?
Fork / Saddle / Brakes / Crank / Gears / Handlebars / Shifters / Wheels: Stock from Felt. Is there something that i should definitely change/upgrade?
Helmet, Lights and Water Bottle: I'd get whatever is in the shop and fits me in size and price. Are there any essentials like air pump or tube fixing kit that I have to get?
Now, for the logistics part:
The biggest concern is how to go about bringing clothes for changing.
How do you go about bringing clothes to work?
What about the sweaty clothes form the ride - is it OK just to put them in a plastic bag till the evening ride back?
I guess wearing a day-old sweaty shirt won't be so pleasant, so how do you go about washing/drying it? Do you bring spare set for the ride back?
One way I consider is driving one day of the week, bringing enough clothes for 4 days of work and leaving it in a bag in the office. This has a disadvantage of "loosing" one day of cycling each week.
Another possibility is to get a rake+bag setup. I'm not sure if there are bags big enough to fit clothes (+shoes?).
Now it takes me around 35 minutes of driving to get to/from work (door-to-door) and that's only if I get out early in the morning (06:15-0:30). If I oversleep and get out at 07:30-08:00 it might take me 50-70 minutes of slow and annoying driving.
Taking into account avg. speed of 40kph/25mph, I can make this ride in about 45 minutes, regardless of time of day.
So the question is: am I right in taking into account avg. speed of 40kph/25mph? Or, am I too optimistic and for these distances the actual speed will be lower?
First of all, thanks for all the help - in the answers and here in comments.
For anyone coming here from a search - read both answers below, a lot of good and practical advice there.
It is indeed a monster question, but during my research I haven't found anyone in my situation. I suspected that there are people with similar experiences, but it's not talked much about. The questions usually divide into two categories - people that commute through the city at 10mph max in full business-ready attire; and people that train for fitness/competition.
My situation, of training-like ride followed by a work day and the logistics + gear required for that - seemed to merit a separate question.
I don't think that there's a need for more answers, the two answers below (separate and, especially, combined) are fully encompassing the breath of the question. Nonetheless, I'd like to have the ability to edit it further after I get the bike and have more experience. I'd like to be able to give feedback back to the community on what worked for me, how I managed different aspects of the issue.
In the end, I'm a newcomer here, so I'd leave it to moderators to decide if they prefer to close the question, leave it on hold, to make a wiki or something else. But I do feel that there are a lot of tips regarding a very specific (niche?) set of boundaries that are not easily found in the great expanses of the internet and thus it would be beneficial to,, at least, keep it available for future searches (i.e. not deleted).